Staging Environment: Content and features may be unstable or change without notice.
Advisory details: gitlab / pypi/nltk/CVE-2026-79657
Advisory ID gitlab/pypi/nltk/CVE-2026-79657
Aliases CVE-2026-79657
GHSA-x99w-6fgc-pmfw
Summary NLTK: Allowlisted pickle loaders still permit code execution in current source The current source tree still allows arbitrary code execution during supposedly safer allowlisted pickle loading. The allowlist trusts whole module namespaces instead of exact safe globals, so crafted pickles can invoke dangerous in-namespace callables through pickle REDUCE.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (4)
CWE-693 Protection Mechanism Failure
CWE-502 Deserialization of Untrusted Data
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-79657.yml
Reference id Reference type URL
https://github.com/nltk/nltk/commit/c3e37113742a1ebeeb4f2ca58941f320f98805ea
https://github.com/nltk/nltk/releases/tag/v3.10.3
https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3735.yaml
CVE-2026-79657 https://nvd.nist.gov/vuln/detail/CVE-2026-79657
GHSA-x99w-6fgc-pmfw https://github.com/advisories/GHSA-x99w-6fgc-pmfw
GHSA-x99w-6fgc-pmfw Advisory https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw
nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserialization Advisory https://www.vulncheck.com/advisories/nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserialization
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-79657.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

There are no SSVC decisions available.