CVE-2025-27516

Name	CVE-2025-27516
Description	Jinja is an extensible templating engine. Prior to 3.1.6, an oversight in how the Jinja sandboxed environment interacts with the \|attr filter allows an attacker that controls the content of a template to execute arbitrary Python code. To exploit the vulnerability, an attacker needs to control the content of a template. Whether that is the case depends on the type of application using Jinja. This vulnerability impacts users of applications which execute untrusted templates. Jinja's sandbox does catch calls to str.format and ensures they don't escape the sandbox. However, it's possible to use the \|attr filter to get a reference to a string's plain format method, bypassing the sandbox. After the fix, the \|attr filter no longer bypasses the environment's attribute lookup. This vulnerability is fixed in 3.1.6.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1099690

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
jinja2 (PTS)	bullseye	2.11.3-1	vulnerable
	bullseye (security)	2.11.3-1+deb11u2	vulnerable
	bookworm	3.1.2-1+deb12u2	vulnerable
	sid, trixie	3.1.5-2	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
jinja2	source	(unstable)	(unfixed)			1099690

Notes

[bookworm] - jinja2 <no-dsa> (Minor issue)
https://github.com/pallets/jinja/security/advisories/GHSA-cpwx-vrp4-4pq7
Fixed by: https://github.com/pallets/jinja/commit/065334d1ee5b7210e1a0a93c37238c86858f2af7 (3.1.6)