Vulnerability-Lookup

PYSEC-2026-87

Vulnerability from pysec - Published: 2026-04-24 17:16 - Updated: 2026-05-20 09:19

Details

lxml is a library for processing XML and HTML in the Python language. Prior to 6.1.0, using either of the two parsers in the default configuration (with resolve_entities=True) allows untrusted XML input to read local files. Setting the resolve_entities option explicitly to resolve_entities='internal' or resolve_entities=False disables the local file access. This vulnerability is fixed in 6.1.0.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Impacted products

Name	purl
lxml	pkg:pypi/lxml

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "lxml",
        "purl": "pkg:pypi/lxml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.3.2",
        "1.3.3",
        "1.3.4",
        "1.3.5",
        "1.3.6",
        "2.0",
        "2.0.10",
        "2.0.11",
        "2.0.4",
        "2.0.5",
        "2.0.6",
        "2.0.7",
        "2.0.8",
        "2.0.9",
        "2.1",
        "2.1.1",
        "2.1.2",
        "2.1.3",
        "2.1.4",
        "2.1.5",
        "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",
        "2.3",
        "2.3.1",
        "2.3.2",
        "2.3.3",
        "2.3.4",
        "2.3.5",
        "2.3.6",
        "3.0",
        "3.0.2",
        "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",
        "3.3.0",
        "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",
        "3.5.0",
        "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",
        "4.3.2",
        "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",
        "4.6.3",
        "4.6.4",
        "4.6.5",
        "4.7.1",
        "4.8.0",
        "4.9.0",
        "4.9.1",
        "4.9.2",
        "4.9.3",
        "4.9.4",
        "5.0.0",
        "5.0.1",
        "5.0.2",
        "5.1.0",
        "5.1.1",
        "5.2.0",
        "5.2.1",
        "5.2.2",
        "5.3.0",
        "5.3.1",
        "5.3.2",
        "5.4.0",
        "6.0.0",
        "6.0.1",
        "6.0.2",
        "6.0.3",
        "6.0.4"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41066",
    "GHSA-vfmq-68hx-4jfw"
  ],
  "details": "lxml is a library for processing XML and HTML in the Python language. Prior to 6.1.0, using either of the two parsers in the default configuration (with resolve_entities=True) allows untrusted XML input to read local files. Setting the resolve_entities option explicitly to resolve_entities=\u0027internal\u0027 or resolve_entities=False disables the local file access. This vulnerability is fixed in 6.1.0.",
  "id": "PYSEC-2026-87",
  "modified": "2026-05-20T09:19:06.179641Z",
  "published": "2026-04-24T17:16:20.933Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw"
    },
    {
      "type": "REPORT",
      "url": "https://bugs.launchpad.net/lxml/+bug/2146291"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-41066 (GCVE-0-2026-41066)

Vulnerability from cvelistv5 – Published: 2026-04-24 16:45 – Updated: 2026-04-24 18:04

Title

lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE

CWE-611 - Improper Restriction of XML External Entity Reference

Assigner

GitHub_M

References

2 references

URL	Tags
https://github.com/lxml/lxml/security/advisories/…	x_refsource_CONFIRM
https://bugs.launchpad.net/lxml/+bug/2146291	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
lxml	lxml	Affected: < 6.1.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-41066",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-24T18:03:40.722204Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-24T18:04:04.548Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "lxml",
          "vendor": "lxml",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.1.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "lxml is a library for processing XML and HTML in the Python language. Prior to 6.1.0, using either of the two parsers in the default configuration (with resolve_entities=True) allows untrusted XML input to read local files. Setting the resolve_entities option explicitly to resolve_entities=\u0027internal\u0027 or resolve_entities=False disables the local file access. This vulnerability is fixed in 6.1.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-611",
              "description": "CWE-611: Improper Restriction of XML External Entity Reference",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-24T16:45:19.617Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw"
        },
        {
          "name": "https://bugs.launchpad.net/lxml/+bug/2146291",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://bugs.launchpad.net/lxml/+bug/2146291"
        }
      ],
      "source": {
        "advisory": "GHSA-vfmq-68hx-4jfw",
        "discovery": "UNKNOWN"
      },
      "title": "lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-41066",
    "datePublished": "2026-04-24T16:45:19.617Z",
    "dateReserved": "2026-04-16T16:43:03.174Z",
    "dateUpdated": "2026-04-24T18:04:04.548Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-VFMQ-68HX-4JFW

Vulnerability from github – Published: 2026-04-21 20:38 – Updated: 2026-04-27 16:43

Summary

lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files

Details

Impact

Using either of the two parsers in the default configuration (with resolve_entities=True) allows untrusted XML input to read local files.

Patches

lxml 6.1.0 changes the default to resolve_entities='internal', thus disallowing local file access by default.

Workarounds

Setting the resolve_entities option explicitly to resolve_entities='internal' or resolve_entities=False disables the local file access.

Resources

Original report: https://bugs.launchpad.net/lxml/+bug/2146291

The default option was changed to resolve_entities='internal' for the normal XML and HTML parsers in lxml 5.0. The default was not changed for iterparse() and ETCompatXMLParser() at the time. lxml 6.1 makes the safe option the default for all parsers.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "lxml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41066"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-611"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-21T20:38:44Z",
    "nvd_published_at": "2026-04-24T17:16:20Z",
    "severity": "HIGH"
  },
  "details": "### Impact\nUsing either of the two parsers in the default configuration (with `resolve_entities=True`) allows untrusted XML input to read local files.\n\n### Patches\nlxml 6.1.0 changes the default to `resolve_entities=\u0027internal\u0027`, thus disallowing local file access by default.\n\n### Workarounds\nSetting the `resolve_entities` option explicitly to `resolve_entities=\u0027internal\u0027` or `resolve_entities=False` disables the local file access.\n\n### Resources\nOriginal report: https://bugs.launchpad.net/lxml/+bug/2146291\n\nThe default option was changed to `resolve_entities=\u0027internal\u0027` for the normal XML and HTML parsers in lxml 5.0. The default was not changed for `iterparse()` and `ETCompatXMLParser()` at the time. lxml 6.1 makes the safe option the default for all parsers.",
  "id": "GHSA-vfmq-68hx-4jfw",
  "modified": "2026-04-27T16:43:20Z",
  "published": "2026-04-21T20:38:44Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41066"
    },
    {
      "type": "WEB",
      "url": "https://bugs.launchpad.net/lxml/+bug/2146291"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/lxml/lxml"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/releases/tag/lxml-6.1.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files"
}

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.

Detection rules are retrieved from Rulezet.

Action not permitted

PYSEC-2026-87

CVE-2026-41066 (GCVE-0-2026-41066)

GHSA-VFMQ-68HX-4JFW

Impact

Patches

Workarounds

Resources

Tags

Sightings

Nomenclature