CVE-2026-79657

9.3 CRITICAL 1% exploit odds Fix listed Code execution Library

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 1.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-08-25 12:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-08 16:17 UTC Last updatedMost recent change to the record

Details

Published: 2026-08-25 12:16 UTC
Last modified: 2026-10-08 16:17 UTC
Exploit probability: 1.3% · EPSS, next 30 days
Weakness: CWE-502 · Unsafe deserialization
Record status: Analyzed

Affected

Nltk < 3.10.3

Attack profile CVSS 4.0 · 9.3

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: None
Confidentiality: High
Integrity: High
Availability: High

Raw vector

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

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Fix and advisories

References

NVD record · CVE.org record