Home / mailings

PDF

[USN-8769-1] phpseclib vulnerability

Posted on 15 September 2026
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-8769-1
September 15, 2026

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

- Ubuntu 26.04 LTS
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

phpseclib could be made to expose sensitive information over the network.

Software Description:
- phpseclib: implementations of an arbitrary-precision integer arithmetic library

Details:

It was discovered that phpseclib did not perform padding validation in
constant time when using AES in CBC mode. A remote attacker could possibly
use this issue to conduct a padding oracle timing attack and obtain
sensitive information.

Update instructions:

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

Ubuntu 26.04 LTS
php-seclib 1.0.24-1ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 24.04 LTS
php-seclib 1.0.23-1ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 22.04 LTS
php-seclib 1.0.20-1+deb12u3build0.22.04.1

Ubuntu 20.04 LTS
php-seclib 1.0.18-2ubuntu0.1~esm2
Available with Ubuntu Pro

Ubuntu 18.04 LTS
php-seclib 1.0.9-1ubuntu0.1~esm2
Available with Ubuntu Pro

Ubuntu 16.04 LTS
php-seclib 1.0.1-3ubuntu0.1+esm1
Available with Ubuntu Pro

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

References:
https://ubuntu.com/security/notices/USN-8769-1
CVE-2023-48795, CVE-2023-52892, CVE-2024-27354, CVE-2024-27355,
CVE-2026-32935

Package Information:
https://launchpad.net/ubuntu/+source/phpseclib/1.0.20-1+deb12u3build0.22.04.1

--===============8114871442041705048==Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature

 

TOP