CVE-2026-71513

Name	CVE-2026-71513
Description	NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables outside the allowlisted namespace. Attackers can craft untrusted transition-parser models that execute arbitrary commands when TransitionParser.parse loads the model through allowlisted_pickle_load.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
nltk (PTS)	bullseye	3.5-1	vulnerable
	bookworm	3.8-1	vulnerable
	trixie	3.9.1-2	vulnerable
	forky, sid	3.10.3-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
nltk	source	(unstable)	(unfixed)

[trixie] - nltk <no-dsa> (Minor issue)
Fixed by: https://github.com/nltk/nltk/commit/c3e37113742a1ebeeb4f2ca58941f320f98805ea (v3.10.3-rc1)