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PYSEC-2021-19
Vulnerability from pysec - Published: 2021-03-21 05:15 - Updated: 2021-03-30 18:47
VLAI
Details
An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Impacted products
| Name | purl | lxml | pkg:pypi/lxml |
|---|
Aliases
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "lxml",
"purl": "pkg:pypi/lxml"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "a5f9cb52079dc57477c460dbe6ba0f775e14a999"
}
],
"repo": "https://github.com/lxml/lxml",
"type": "GIT"
},
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.6.3"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.9",
"0.9.1",
"0.9.2",
"1.0.beta",
"1.0",
"1.0.1",
"1.0.2",
"1.0.3",
"1.0.4",
"1.1alpha",
"1.1beta",
"1.1",
"1.1.1",
"1.1.2",
"1.2",
"1.2.1",
"1.3beta",
"1.3",
"1.3.1",
"1.3.2",
"1.3.3",
"1.3.4",
"1.3.5",
"1.3.6",
"2.0alpha1",
"2.0alpha2",
"2.0alpha3",
"2.0alpha4",
"2.0alpha5",
"2.0alpha6",
"2.0beta1",
"2.0beta2",
"2.0",
"2.0.1",
"2.0.2",
"2.0.3",
"2.0.4",
"2.0.5",
"2.0.6",
"2.0.7",
"2.0.8",
"2.0.9",
"2.0.10",
"2.0.11",
"2.1alpha1",
"2.1beta1",
"2.1beta2",
"2.1beta3",
"2.1",
"2.1.1",
"2.1.2",
"2.1.3",
"2.1.4",
"2.1.5",
"2.2alpha1",
"2.2beta1",
"2.2beta2",
"2.2beta3",
"2.2beta4",
"2.2",
"2.2.1",
"2.2.2",
"2.2.3",
"2.2.4",
"2.2.5",
"2.2.6",
"2.2.7",
"2.2.8",
"2.3alpha1",
"2.3alpha2",
"2.3beta1",
"2.3",
"2.3.1",
"2.3.2",
"2.3.3",
"2.3.4",
"2.3.5",
"2.3.6",
"3.0",
"3.0.1",
"3.0.2",
"3.1beta1",
"3.1.0",
"3.1.1",
"3.1.2",
"3.2.0",
"3.2.1",
"3.2.2",
"3.2.3",
"3.2.4",
"3.2.5",
"3.3.0beta1",
"3.3.0beta2",
"3.3.0beta3",
"3.3.0beta4",
"3.3.0beta5",
"3.3.0",
"3.3.1",
"3.3.2",
"3.3.3",
"3.3.4",
"3.3.5",
"3.3.6",
"3.4.0",
"3.4.1",
"3.4.2",
"3.4.3",
"3.4.4",
"3.5.0b1",
"3.5.0",
"3.6.0",
"3.6.1",
"3.6.2",
"3.6.3",
"3.6.4",
"3.7.0",
"3.7.1",
"3.7.2",
"3.7.3",
"3.8.0",
"4.0.0",
"4.1.0",
"4.1.1",
"4.2.0",
"4.2.1",
"4.2.2",
"4.2.3",
"4.2.4",
"4.2.5",
"4.2.6",
"4.3.0",
"4.3.1",
"4.3.2",
"4.3.3",
"4.3.4",
"4.3.5",
"4.4.0",
"4.4.1",
"4.4.2",
"4.4.3",
"4.5.0",
"4.5.1",
"4.5.2",
"4.6.0",
"4.6.1",
"4.6.2"
]
}
],
"aliases": [
"CVE-2021-28957",
"GHSA-jq4v-f5q6-mjqq"
],
"details": "An XSS vulnerability was discovered in python-lxml\u0027s clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.",
"id": "PYSEC-2021-19",
"modified": "2021-03-30T18:47:00Z",
"published": "2021-03-21T05:15:00Z",
"references": [
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "FIX",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "ADVISORY",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
}
]
}
BREW-BZT-CVE-2021-28957 (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:38 – Updated: 2026-09-10 18:58 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.2",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "bzt",
"purl": "pkg:brew/bzt"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.16.51_2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.2",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.2"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-bzt-CVE-2021-28957",
"modified": "2026-09-10T18:58:25Z",
"published": "2026-08-13T16:38:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-CHARMCRAFT-CVE-2021-28957 (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:39 – Updated: 2026-09-09 23:46 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.2",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "charmcraft",
"purl": "pkg:brew/charmcraft"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.2",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.2"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-charmcraft-CVE-2021-28957",
"modified": "2026-09-09T23:46:28Z",
"published": "2026-08-13T16:39:06Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-CPPMAN-CVE-2021-28957 (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:41 – Updated: 2026-09-09 23:48 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.0",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "cppman",
"purl": "pkg:brew/cppman"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.6.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.0",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.0"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-cppman-CVE-2021-28957",
"modified": "2026-09-09T23:48:52Z",
"published": "2026-08-13T16:41:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-CYCLONEDX-PYTHON-CV… (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:42 – Updated: 2026-09-09 23:50 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.1",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "cyclonedx-python",
"purl": "pkg:brew/cyclonedx-python"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "7.3.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.1",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.1"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-cyclonedx-python-CVE-2021-28957",
"modified": "2026-09-09T23:50:38Z",
"published": "2026-08-13T16:42:07Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-DNSROBOCERT-CVE-202… (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:43 – Updated: 2026-09-09 23:51 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.1",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "dnsrobocert",
"purl": "pkg:brew/dnsrobocert"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.27.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.1",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.1"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-dnsrobocert-CVE-2021-28957",
"modified": "2026-09-09T23:51:44Z",
"published": "2026-08-13T16:43:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-DUPLICITY-CVE-2021-28957 (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:44 – Updated: 2026-09-09 23:52 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.2",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "duplicity",
"purl": "pkg:brew/duplicity"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.1.0_2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.2",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.2"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-duplicity-CVE-2021-28957",
"modified": "2026-09-09T23:52:33Z",
"published": "2026-08-13T16:44:03Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-ENEX2NOTION-CVE-202… (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:45 – Updated: 2026-09-10 19:07 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.0.2",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "enex2notion",
"purl": "pkg:brew/enex2notion"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.3.1_23"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.0.2",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.0.2"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-enex2notion-CVE-2021-28957",
"modified": "2026-09-10T19:07:42Z",
"published": "2026-08-13T16:45:05Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-FAVA-CVE-2021-28957 (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:46 – Updated: 2026-09-17 18:01 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.1",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "fava",
"purl": "pkg:brew/fava"
},
"ranges": [
{
"events": [
{
"introduced": "1.14"
},
{
"fixed": "1.19"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.1",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.1"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-fava-CVE-2021-28957",
"modified": "2026-09-17T18:01:22Z",
"published": "2026-08-13T16:46:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-FDROIDSERVER-CVE-20… (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:46 – Updated: 2026-09-10 19:12 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.3",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "fdroidserver",
"purl": "pkg:brew/fdroidserver"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.4.5_4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.3",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.3"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-fdroidserver-CVE-2021-28957",
"modified": "2026-09-10T19:12:43Z",
"published": "2026-08-13T16:46:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
BREW-FONTTOOLS-CVE-2021-28957 (GHSA-JQ4V-F5Q6-MJQQ)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:48 – Updated: 2026-09-12 09:00 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details
An XSS vulnerability was discovered in the python lxml clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
Severity
6.1 (Medium)
References
| URL | Type | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "lxml",
"resource_purl": "pkg:pypi/lxml@6.1.3",
"upstream_fixed_in": "4.6.3"
},
"package": {
"ecosystem": "Homebrew",
"name": "fonttools",
"purl": "pkg:brew/fonttools"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.63.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/lxml@6.1.3",
"name": "lxml",
"resource": "lxml",
"strategy": "registry",
"subject_version": "6.1.3"
}
]
},
"details": "An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.",
"id": "BREW-fonttools-CVE-2021-28957",
"modified": "2026-09-12T09:00:51Z",
"published": "2026-08-13T16:48:19Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
},
{
"type": "WEB",
"url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4880"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210521-0004"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202208-06"
},
{
"type": "WEB",
"url": "https://pypi.org/project/lxml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/lxml/lxml"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/lxml/+bug/1888153"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "lxml vulnerable to Cross-Site Scripting ",
"upstream": [
"GHSA-jq4v-f5q6-mjqq",
"CVE-2021-28957",
"PYSEC-2021-19"
]
}
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Trend slope:
-
(linear fit over daily sighting counts)
Show additional events:
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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