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Related vulnerabilities
PYSEC-2026-3748
Vulnerability from pysec - Published: 2026-08-25 02:16 - Updated: 2026-09-02 08:34
VLAI
Details
NLTK versions before 3.10.3 use xml.etree.ElementTree to parse XML in multiple modules, which honors entity declarations in document DTDs. Attackers can craft XML payloads with nested entity declarations that expand from hundreds of bytes to megabytes in memory, causing denial of service.
Severity
Impacted products
| Name | purl | nltk | pkg:pypi/nltk |
|---|
Aliases
{
"affected": [
{
"ecosystem_specific": {},
"package": {
"ecosystem": "PyPI",
"name": "nltk",
"purl": "pkg:pypi/nltk"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.10.3"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.8",
"0.9",
"0.9.3",
"0.9.4",
"0.9.5",
"0.9.6",
"0.9.7",
"0.9.8",
"0.9.9",
"2.0.1",
"2.0.1rc1",
"2.0.1rc2-git",
"2.0.1rc3",
"2.0.1rc4",
"2.0.2",
"2.0.3",
"2.0.4",
"2.0.5",
"2.0b4",
"2.0b5",
"2.0b6",
"2.0b7",
"2.0b8",
"2.0b9",
"3.0.0",
"3.0.0b1",
"3.0.0b2",
"3.0.1",
"3.0.2",
"3.0.3",
"3.0.4",
"3.0.5",
"3.1",
"3.10.0",
"3.10.1",
"3.10.2",
"3.2",
"3.2.1",
"3.2.2",
"3.2.3",
"3.2.4",
"3.2.5",
"3.3",
"3.4",
"3.4.1",
"3.4.2",
"3.4.3",
"3.4.4",
"3.4.5",
"3.5",
"3.5b1",
"3.6",
"3.6.1",
"3.6.2",
"3.6.3",
"3.6.4",
"3.6.5",
"3.6.6",
"3.6.7",
"3.7",
"3.8",
"3.8.1",
"3.9",
"3.9.1",
"3.9.2",
"3.9.3",
"3.9.4",
"3.9b1"
]
}
],
"aliases": [
"CVE-2026-78681",
"GHSA-97qj-x29f-37w7"
],
"details": "NLTK versions before 3.10.3 use xml.etree.ElementTree to parse XML in multiple modules, which honors entity declarations in document DTDs. Attackers can craft XML payloads with nested entity declarations that expand from hundreds of bytes to megabytes in memory, causing denial of service.",
"id": "PYSEC-2026-3748",
"modified": "2026-09-02T08:34:35.278870Z",
"published": "2026-08-25T02:16:52.750Z",
"references": [
{
"type": "ADVISORY",
"url": "https://www.vulncheck.com/advisories/nltk-before-entity-expansion-dos-via-elementtree"
},
{
"type": "EVIDENCE",
"url": "https://github.com/nltk/nltk/security/advisories/GHSA-97qj-x29f-37w7"
}
],
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}