HighFix available
nltk — security advisory
NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.
- Products
- nltk
- Affected versions
- 3.10.0-1, 3.10.1-1, 3.10.3-1, 3.8-1, 3.8.1-1, 3.9.1-1, 3.9.1-2, 3.9.2-1, 3.9.3-1
- Fixed versions
- 3.10.0-1
- CVEs
- CVE-2026-70626
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 16:29 UTC · Revision 1
Source evidence
NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.
osv:DEBIAN-CVE-2026-70626
nltk
Fixed versions: Not specified
nltk
Fixed versions: Not specified
nltk
Fixed versions: 3.10.0-1
Complete source record
{
"id": "d942d315896b603694e2caeba536f44ce487b37c70a9b885b339a1f6927867bc",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-70626",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-70626",
"summary": "NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.",
"evidence": "osv:DEBIAN-CVE-2026-70626",
"products": [
{
"name": {
"value": "nltk",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.10.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.10.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.10.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.8-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.8.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.9.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.9.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "3.9.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.9.3-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "nltk",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.10.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.10.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.10.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.9.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "3.9.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.9.3-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "nltk",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.10.0-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "3.9.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "3.9.2-1",
"evidence": "/affected/2/versions"
},
{
"value": "3.9.3-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-70626",
"aliases": [
"DEBIAN-CVE-2026-70626"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nltk",
"purl": "pkg:deb/debian/nltk?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"3.10.0-1",
"3.10.1-1",
"3.10.3-1",
"3.8-1",
"3.8.1-1",
"3.9.1-1",
"3.9.1-2",
"3.9.2-1",
"3.9.3-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-70626.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nltk",
"purl": "pkg:deb/debian/nltk?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"3.10.0-1",
"3.10.1-1",
"3.10.3-1",
"3.9.1-2",
"3.9.2-1",
"3.9.3-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-70626.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.10.0-1"
}
]
}
],
"package": {
"name": "nltk",
"purl": "pkg:deb/debian/nltk?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"3.9.1-2",
"3.9.2-1",
"3.9.3-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-70626.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-15T09:47:33.030912961Z",
"provider": "osv",
"upstream": [
"CVE-2026-70626"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-70626"
]
},
"related_cves": [
{
"value": "CVE-2026-70626",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 327675,
"published_at": "2026-08-22T15:16:21.1+00:00"
}