PyPI/nltk CVE-2026-12261: medium 5.3, EPSS 0.21%

NLTK downloader allows cross-package resource and model poisoning

Action: Upgrade nltk to 3.10.0 or later.

pip install nltk==3.10.0

Affected

Fixed versions

Sources

• osv: GHSA-ffj6-66c4-86gw
• https://nvd.nist.gov/vuln/detail/CVE-2026-12261
• https://github.com/nltk/nltk/pull/3625
• https://github.com/nltk/nltk/commit/7a5740af89feeb739193db766e11e85dfe78339c
• https://github.com/nltk/nltk
• https://github.com/nltk/nltk/releases/tag/v3.10.0
• https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3954.yaml
• https://huntr.com/bounties/8b8c381e-08a8-4e4f-bb46-a320c96a364f

CVE-2026-12261 · published 2026-08-07T09:31:52Z · modified 2026-10-02T23:40:50.637389089Z · JSON