CVE-2026-79657

critical · 9.3

NLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire module namespaces instead of specific safe callables. Attackers can craft malicious pickle payloads invoking dangerous in-namespace functions like ReppTokenizer._execute and numpy.f2py.crackfortran.myeval through pickle REDUCE to execute arbitrary commands during model or tokenizer artifact loading.

9.3

CVSS

1.3%

EPSS (exploit prob.)

70th

EPSS percentile

2026-08-25

Published

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-502

Affected products

Vendor	Product	Affected versions
nltk	nltk	< 3.10.3

Check a specific version with /api/v1/cve/match.

References

https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw
https://www.vulncheck.com/advisories/nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserialization
https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-79657