Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

CVE-2026-79676NLTK before 3.10.3 Path Traversal via Symlink Bypass

Medium 5.9

In plain English

A medium-severity path traversal in nltk from nltk. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.4%top 61.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

NLTK versions before 3.10.3 contain a path traversal vulnerability in corpus readers that reopen root-derived paths using built-in open() instead of nltk.pathsec.open(), allowing symlinks to escape trusted roots. Attackers who stage symlinked corpus files under a trusted data root can disclose outside-root content through normal corpus reader methods like channels(), domains(), and synonyms().

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	nltk	no fix listed	DEBIAN-CVE-2026-79676
Debian:13	nltk	no fix listed	DEBIAN-CVE-2026-79676
Debian:14	nltk	3.10.3-1	DEBIAN-CVE-2026-79676
PyPI	nltk	3.10.3	GHSA-p4rw-rvv2-7xwr
PyPI	nltk	3.10.3	PYSEC-2026-3737

Affected products (as reported)

Vendor	Product	Versions
nltk	nltk	0 – before 3.10.3

Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References

GitHub Security Advisory (GHSA-p4rw-rvv2-7xwr) vendor-advisory
VulnCheck Advisory: NLTK before 3.10.3 Path Traversal via Symlink Bypass third-party-advisory