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[USN-7851-1] runC vulnerabilities

Posted on 05 November 2025
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-7851-1
November 04, 2025

runc-app, runc-stable vulnerabilities
==========================================================================
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:

Several security issues were fixed in runC.

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

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 1.3.3-0ubuntu1~25.10.2
runc-stable 1.3.3-0ubuntu1~25.10.2

Ubuntu 25.04
runc 1.3.3-0ubuntu1~25.04.2

Ubuntu 24.04 LTS
runc 1.3.3-0ubuntu1~24.04.2

Ubuntu 22.04 LTS
runc 1.3.3-0ubuntu1~22.04.2

This update uses a new upstream release, which includes additional bug
fixes. In general, a standard system update will make all the necessary
changes.

References:
https://ubuntu.com/security/notices/USN-7851-1
CVE-2025-31133, CVE-2025-52565, CVE-2025-52881

Package Information:
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~25.10.2
https://launchpad.net/ubuntu/+source/runc-stable/1.3.3-0ubuntu1~25.10.2
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~25.04.2
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~24.04.2
https://launchpad.net/ubuntu/+source/runc-app/1.3.3-0ubuntu1~22.04.2

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