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[USN-7851-2] runC regression

Posted on 24 November 2025
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-7851-2
November 24, 2025

runc-app, runc-stable regression
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 25.10
- Ubuntu 25.04
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

Summary:

USN-7851-1 introduced a regression in runC

Software Description:
- runc-app: Open Container Project
- runc-stable: Open Container Project

Details:

USN-7851-1 fixed vulnerabilities in runC. The introduction of a new
upstream release has caused regressions in runc-app and runc-stable.
This update fixes the problem.

Original advisory details:

Lei Wang and Li Fubang discovered that runC incorrectly handled masked
paths. An attacker could possibly replace a container's /dev/null
with a symlink to some other procfs file and possibly escape a container.
(CVE-2025-31133)

Lei Wang and Li Fubang discovered that runC incorrectly handled the
/dev/console bind-mounts. An attacker could potentially exploit this issue
to build-mount a symlink and escape a container. (CVE-2025-52565)

Li Fubang and Tõnis Tiigi discovered that the fix for CVE-2019-16884 was
incomplete. An attacker could possibly use this issue to cause a denial of
service or escape the container. (CVE-2025-52881)

Update instructions:

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

Ubuntu 25.10
runc 1.3.3-0ubuntu1~25.10.3
runc-stable 1.3.3-0ubuntu1~25.10.3

Ubuntu 25.04
runc 1.3.3-0ubuntu1~25.04.3

Ubuntu 24.04 LTS
runc 1.3.3-0ubuntu1~24.04.3

Ubuntu 22.04 LTS
runc 1.3.3-0ubuntu1~22.04.3

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

References:
https://ubuntu.com/security/notices/USN-7851-2
https://ubuntu.com/security/notices/USN-7851-1
https://launchpad.net/bugs/2130744

Package Information:
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~25.10.3
https://launchpad.net/ubuntu/+source/runc-stable/1.3.3-0ubuntu1~25.10.3
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~25.04.3
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~24.04.3
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~22.04.3

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