A PMIx security update has been released for Ubuntu Linux 18.04 LTS, 20.04 LTS, and 22.04 LTS.

[USN-6434-1] PMIx vulnerability

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Ubuntu Security Notice USN-6434-1
October 17, 2023

pmix vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 22.04 LTS (Available with Ubuntu Pro)
- Ubuntu 20.04 LTS (Available with Ubuntu Pro)
- Ubuntu 18.04 LTS (Available with Ubuntu Pro)

Summary:

PMIx could be made to overwrite files.

Software Description:
- pmix: Process Management Interface (Exascale) library - tools

Details:

Francois Diakhate discovered that PMIx did not properly handle race
conditions in the pmix library, which could lead to unwanted privilege
escalation. An attacker could possibly use this issue to obtain ownership
of an arbitrary file on the filesystem, under the default configuration
of the application.

Update instructions:

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

Ubuntu 22.04 LTS (Available with Ubuntu Pro):
libpmix-bin 4.1.2-2ubuntu1+esm1
libpmix2 4.1.2-2ubuntu1+esm1
python3-pmix 4.1.2-2ubuntu1+esm1

Ubuntu 20.04 LTS (Available with Ubuntu Pro):
libpmi1-pmix 3.1.5-1ubuntu0.1~esm1
libpmi2-pmix 3.1.5-1ubuntu0.1~esm1
libpmix2 3.1.5-1ubuntu0.1~esm1

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
libpmi1-pmix 2.1.1~rc1-1ubuntu0.1~esm1
libpmi2-pmix 2.1.1~rc1-1ubuntu0.1~esm1
libpmix2 2.1.1~rc1-1ubuntu0.1~esm1

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

References:
https://ubuntu.com/security/notices/USN-6434-1
CVE-2023-41915