Critical severity9.8NVD Advisory· Published Aug 25, 2026· Updated Aug 31, 2026
CVE-2026-79657
CVE-2026-79657
Description
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
nltkPyPI | < 3.10.3 | 3.10.3 |
Affected products
2Patches
Vulnerability mechanics
References
7- github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfwnvdExploitVendor AdvisoryWEB
- github.com/advisories/GHSA-x99w-6fgc-pmfwghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-79657ghsaADVISORY
- www.vulncheck.com/advisories/nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserializationnvdThird Party AdvisoryWEB
- github.com/nltk/nltk/commit/c3e37113742a1ebeeb4f2ca58941f320f98805eaghsaWEB
- github.com/nltk/nltk/releases/tag/v3.10.3ghsaWEB
- github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3735.yamlghsaWEB
News mentions
1- Nltk Library: 16 Vulnerabilities Including Critical RCE Disclosed in BatchVypr Intelligence · Aug 27, 2026