CVE-2025-27516

NameCVE-2025-27516
DescriptionJinja 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1099690

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
jinja2 (PTS)bullseye2.11.3-1vulnerable
bullseye (security)2.11.3-1+deb11u2vulnerable
bookworm3.1.2-1+deb12u2vulnerable
sid, trixie3.1.6-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
jinja2source(unstable)3.1.6-11099690

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)

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