A strongSwan security update has been released for Ubuntu Linux 20.04 LTS, 22.04 LTS, 23.04 LTS, and 23.10.

[USN-6488-1] strongSwan vulnerability

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Ubuntu Security Notice USN-6488-1
November 20, 2023

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

- Ubuntu 23.10
- Ubuntu 23.04
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS

Summary:

strongSwan could be made to crash or run programs if it received
specially crafted network traffic.

Software Description:
- strongswan: IPsec VPN solution

Details:

Florian Picca discovered that strongSwan incorrectly handled certain DH
public values. A remote attacker could use this issue to cause strongSwan
to crash, resulting in a denial of service, or possibly execute arbitrary
code.

Update instructions:

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

Ubuntu 23.10:
libstrongswan 5.9.11-1ubuntu1.1
strongswan 5.9.11-1ubuntu1.1

Ubuntu 23.04:
libstrongswan 5.9.8-3ubuntu4.1
strongswan 5.9.8-3ubuntu4.1

Ubuntu 22.04 LTS:
libstrongswan 5.9.5-2ubuntu2.2
strongswan 5.9.5-2ubuntu2.2

Ubuntu 20.04 LTS:
libstrongswan 5.8.2-1ubuntu3.6
strongswan 5.8.2-1ubuntu3.6

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

References:
https://ubuntu.com/security/notices/USN-6488-1
CVE-2023-41913

Package Information:
https://launchpad.net/ubuntu/+source/strongswan/5.9.11-1ubuntu1.1
https://launchpad.net/ubuntu/+source/strongswan/5.9.8-3ubuntu4.1
https://launchpad.net/ubuntu/+source/strongswan/5.9.5-2ubuntu2.2
https://launchpad.net/ubuntu/+source/strongswan/5.8.2-1ubuntu3.6