[USN-8563-1] nginx vulnerabilities

[noreply+usn-bot at canonical.com]

==========================================================================
Ubuntu Security Notice USN-8563-1
July 20, 2026

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

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

Summary:

Several security issues were fixed in nginx.

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

Details:

It was discovered that nginx incorrectly handled certain map directives
using regex matching and capture variables. A remote attacker could use
this issue to cause nginx to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2026-42533)

It was discovered that nginx had a use-after-free vulnerability in the
ngx_http_ssi_module module when configured with Server-Side Includes,
proxy_pass, and proxy buffering disabled directives. An attacker able to
intercept traffic and control responses from an upstream server could
possibly use this issue to cause nginx to crash, resulting in a denial of
service. (CVE-2026-56434)

It was discovered that nginx incorrectly handled certain requests in the
ngx_http_slice_module module. A remote attacker could possibly use this
issue to obtain sensitive information or cause nginx to crash, resulting
in a denial of service. (CVE-2026-60005)

Update instructions:

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

Ubuntu 26.04 LTS
  nginx                           1.28.3-2ubuntu1.7
  nginx-core                      1.28.3-2ubuntu1.7
  nginx-extras                    1.28.3-2ubuntu1.7
  nginx-full                      1.28.3-2ubuntu1.7
  nginx-light                     1.28.3-2ubuntu1.7

Ubuntu 24.04 LTS
  nginx                           1.24.0-2ubuntu7.14
  nginx-core                      1.24.0-2ubuntu7.14
  nginx-extras                    1.24.0-2ubuntu7.14
  nginx-full                      1.24.0-2ubuntu7.14
  nginx-light                     1.24.0-2ubuntu7.14

Ubuntu 22.04 LTS
  nginx                           1.18.0-6ubuntu14.17
  nginx-core                      1.18.0-6ubuntu14.17
  nginx-extras                    1.18.0-6ubuntu14.17
  nginx-full                      1.18.0-6ubuntu14.17
  nginx-light                     1.18.0-6ubuntu14.17

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

References:
  https://ubuntu.com/security/notices/USN-8563-1
  CVE-2026-42533, CVE-2026-56434, CVE-2026-60005

Package Information:
  https://launchpad.net/ubuntu/+source/nginx/1.28.3-2ubuntu1.7
  https://launchpad.net/ubuntu/+source/nginx/1.24.0-2ubuntu7.14
  https://launchpad.net/ubuntu/+source/nginx/1.18.0-6ubuntu14.17
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