Vulnerability in Nltk
CVE-2026-81726
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:L.
EPSS exploit prediction
EPSS: 0.003 (25.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/nltk/nltk/security/advisories/GHSA-8mgp-746c-j5xp (Exploit, vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/nltk-through-3.10.3-path-traversal-via-model-artif… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-81726?
- CVE-2026-81726 is a high-severity vulnerability in Nltk, classified under External Control of File Name or Path. CVSS score: 7.0/10. Published 2026-08-27.
- How severe is CVE-2026-81726?
- High severity. CVSS v3 base score is 7.0 out of 10.