by Kastro
Paper/Archive/CVE-2026-79657

CVE-2026-79657

nltk nltk — NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization

EPSS 1%public exploitCVSS 9.8
critical.is priorityof 100
53
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 69.7.697 × 2013.9Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
nltk< 3.10.33.10.3CNA

Scores by source

VulnCheck (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitgithub.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfwwriteupvulncheck.com/advisories/nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserialization