CVE-2026-79657CWE-502insecure-deserialization

CVE-2026-79657

Critical · published August 25, 2026

CVSS v3.1
9.8
EPSS
1%
Percentile
69.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
9.3 · 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
EPSS
0.01267 · 69.5th percentile
Weakness
CWE-502 · Deserialization of Untrusted Data
Published
2026-08-25T16:16Z
Affected products (1)
ProductVersionsFixed in
nltk/nltk< 3.10.33.10.3
References (3)
https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw · [email protected]https://www.vulncheck.com/advisories/nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserialization · [email protected]https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 27 AUG 06:46Z
    EPSS moved — → 1%
    epss
  • 25 AUG 11:33Z
    NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization
    cvelistv5