medium
5.4
CWE
1336
EPSS
0.065%
Advisory Published
Advisory Published
Updated

CVE-2025-27516: Jinja sandbox breakout through attr filter selecting format method

First published: Wed Mar 05 2025(Updated: )

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.

Credit: security-advisories@github.com

Affected SoftwareAffected VersionHow to fix
pip/Jinja2<=3.1.5
3.1.6
IBM Storage Defender Resiliency Service<=2.0.0 - 2.0.12
debian/jinja2<=2.11.3-1<=3.1.2-1+deb12u2
2.11.3-1+deb11u3
3.1.6-1

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Reference Links

Parent vulnerabilities

(Appears in the following advisories)

Frequently Asked Questions

  • What is the severity of CVE-2025-27516?

    CVE-2025-27516 is rated as a critical vulnerability due to its potential to enable arbitrary code execution.

  • How do I fix CVE-2025-27516?

    To mitigate CVE-2025-27516, upgrade Jinja2 to version 3.1.6 or later.

  • Who is affected by CVE-2025-27516?

    CVE-2025-27516 affects users of Jinja2 versions 3.1.5 and earlier.

  • What does CVE-2025-27516 allow an attacker to do?

    CVE-2025-27516 allows an attacker to execute arbitrary Python code through controlled template content.

  • How can I identify if I'm vulnerable to CVE-2025-27516?

    You can identify if you're vulnerable to CVE-2025-27516 by checking if you are using Jinja2 version 3.1.5 or earlier.

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