CVE-2026-79657 PUBLISHED

NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization

Assigner: VulnCheck
Reserved: 25.08.2026 Published: 25.08.2026 Updated: 25.08.2026

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.

CVSS 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
CVSS Score: 9.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 9.8

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	nltk
Product	nltk
Versions	Default: unaffected affected from 0 to 3.10.3 (excl.) Version 3.10.3 is unaffected

CVE-2026-79657 PUBLISHED

NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization

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Product Status

Credits

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Problem Types