==========================================================================
Ubuntu Security Notice USN-8398-2
June 09, 2026

nginx regression
==========================================================================

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

- Ubuntu 26.04 LTS
- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

Summary:

USN-8398-1 introduced a regression in nginx

Software Description:
- nginx: small, powerful, scalable web/proxy server

Details:

USN-8398-1 fixed a vulnerability in nginx. The update introduced a
regression causing nginx to crash when being used with external modules.
This update reverts the fix for CVE-2026-49975 pending further
investigation.

We apologize for the inconvenience.

Original advisory details:

 It was discovered that nginx incorrectly handled certain cookie headers in
 the HTTP/2 implementation. A remote attacker could possibly use this issue
 to cause nginx to consume excessive resources, resulting in a denial of
 service.

Update instructions:

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

Ubuntu 26.04 LTS
  nginx                           1.28.3-2ubuntu1.4
  nginx-core                      1.28.3-2ubuntu1.4
  nginx-extras                    1.28.3-2ubuntu1.4
  nginx-full                      1.28.3-2ubuntu1.4
  nginx-light                     1.28.3-2ubuntu1.4

Ubuntu 25.10
  nginx                           1.28.0-6ubuntu1.6
  nginx-core                      1.28.0-6ubuntu1.6
  nginx-extras                    1.28.0-6ubuntu1.6
  nginx-full                      1.28.0-6ubuntu1.6
  nginx-light                     1.28.0-6ubuntu1.6

Ubuntu 24.04 LTS
  nginx                           1.24.0-2ubuntu7.11
  nginx-core                      1.24.0-2ubuntu7.11
  nginx-extras                    1.24.0-2ubuntu7.11
  nginx-full                      1.24.0-2ubuntu7.11
  nginx-light                     1.24.0-2ubuntu7.11

Ubuntu 22.04 LTS
  nginx                           1.18.0-6ubuntu14.14
  nginx-core                      1.18.0-6ubuntu14.14
  nginx-extras                    1.18.0-6ubuntu14.14
  nginx-full                      1.18.0-6ubuntu14.14
  nginx-light                     1.18.0-6ubuntu14.14

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

References:
  https://ubuntu.com/security/notices/USN-8398-2
  https://ubuntu.com/security/notices/USN-8398-1
  https://launchpad.net/bugs/2155992

Package Information:
  https://launchpad.net/ubuntu/+source/nginx/1.28.3-2ubuntu1.4
  https://launchpad.net/ubuntu/+source/nginx/1.28.0-6ubuntu1.6
  https://launchpad.net/ubuntu/+source/nginx/1.24.0-2ubuntu7.11
  https://launchpad.net/ubuntu/+source/nginx/1.18.0-6ubuntu14.14