Vulnerability · Published Oct 13, 2026 · Assigned by VulnCheck
CVE-2026-109956NLTK through 3.10.3 Path Traversal via WekaClassifier Model Path
High 7.0
In plain English
A high-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 0.3% (higher than 25% 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 75.1% 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 WekaClassifier that allows attackers to bypass nltk.pathsec containment by supplying unvalidated model paths. Attackers controlling the model_filename or model argument can make the weka JVM write files via -d or probe files via -l outside allowed data roots.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | nltk | no fix listed | DEBIAN-CVE-2026-109956 |
| Debian:13 | nltk | no fix listed | DEBIAN-CVE-2026-109956 |
| Debian:14 | nltk | no fix listed | DEBIAN-CVE-2026-109956 |
| PyPI | nltk | 3.10.4 | GHSA-j456-xh4h-cpf2 |
| Ubuntu:26.10 | nltk | no fix listed | UBUNTU-CVE-2026-109956 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
References
- GitHub Security Advisory (GHSA-j456-xh4h-cpf2) vendor-advisory
- VulnCheck Advisory: NLTK through 3.10.3 Path Traversal via WekaClassifier Model Path third-party-advisory