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Ubuntu Security Notice USN-7343-2
March 12, 2025

jinja2 regression
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

USN-7343-1 introduced a regression in Jinja2.

Software Description:
- jinja2: small but fast and easy to use stand-alone template engine

Details:

USN-7343-1 fixed vulnerabilities in Jinja2. The update introduced a
regression when attempting to import Jinja2 on Ubuntu 18.04 LTS and
Ubuntu 20.04 LTS. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Rafal Krupinski discovered that Jinja2 did not properly restrict
the execution of code in situations where templates are used maliciously.
An attacker with control over a template's filename and content could
potentially use this issue to enable the execution of arbitrary code.
This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS.
(CVE-2024-56201)

It was discovered that Jinja2 sandboxed environments could be escaped
through a call to a string format method. An attacker could possibly use
this issue to enable the execution of arbitrary code. This issue only
affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2024-56326)

It was discovered that Jinja2 sandboxed environments could be escaped
through the malicious use of certain filters. An attacker could possibly
use this issue to enable the execution of arbitrary code. (CVE-2025-27516)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS
  python-jinja2                   2.10.1-2ubuntu0.6
  python3-jinja2                  2.10.1-2ubuntu0.6

Ubuntu 18.04 LTS
  python-jinja2                   2.10-1ubuntu0.18.04.1+esm5
                                  Available with Ubuntu Pro
  python3-jinja2                  2.10-1ubuntu0.18.04.1+esm5
                                  Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-7343-2
https://ubuntu.com/security/notices/USN-7343-1
https://launchpad.net/bugs/2102129

Package Information:
https://launchpad.net/ubuntu/+source/jinja2/2.10.1-2ubuntu0.6