Vulnerability · Published Aug 27, 2026 · Assigned by VulnCheck

CVE-2026-81726NLTK through 3.10.3 Path Traversal via Model-Artifact APIs

High 7.0

In plain English

A high-severity security flaw in nltk from nltk. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.0High

Exploit odds (30 days)0.3%top 72.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that bypass pathsec enforcement by using raw file operations on caller-controlled paths. Attackers can read or write files outside allowed sandbox roots through TransitionParser, AveragedPerceptron, PerceptronTagger, and maxent parameter APIs when pathsec is enabled.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	nltk	no fix listed	DEBIAN-CVE-2026-81726
Debian:13	nltk	no fix listed	DEBIAN-CVE-2026-81726
Debian:14	nltk	no fix listed	DEBIAN-CVE-2026-81726
PyPI	nltk	3.10.4	GHSA-8mgp-746c-j5xp
PyPI	nltk	3.10.3	PYSEC-2026-3740
Ubuntu:26.10	nltk	no fix listed	UBUNTU-CVE-2026-81726

Affected products (as reported)

Vendor	Product	Versions
nltk	nltk	0 – through 3.10.3

Weakness: CWE-73 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:L

References

GitHub Security Advisory (GHSA-8mgp-746c-j5xp) vendor-advisory
VulnCheck Advisory: NLTK through 3.10.3 Path Traversal via Model-Artifact APIs third-party-advisory