Ubuntu 26.04 LTS Nginx Serious DoS Remote Attack Vulnerabilities USN-8354-1

ubuntu

June 1, 2026

Several security issues were fixed in nginx.

Summary

Several security issues were fixed in nginx.

Software Description:

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

Details:

It was discovered that nginx did not properly validate source addresses in

the HTTP/3 QUIC module. A remote attacker could possibly use this issue to

bypass authorization checks or rate limiting. This issue only affected

Ubuntu 25.04 and Ubuntu 25.10. (CVE-2026-40460)

It was discovered that nginx contained a use-after-free vulnerability in

the ngx_http_ssl_module module when client certificate verification and

OCSP validation were enabled. A remote attacker could use this issue to

cause nginx to crash, resulting in a denial of service, or possibly modify

data in memory. (CVE-2026-40701)

It was discovered that nginx did not properly handle certain proxied

responses in the ngx_http_charset_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-2026-42...

Read the Full Advisory

Topics Covered

security advisory denial of service critical remote attack Ubuntu nginx

Update Instructions

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

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

Ubuntu 25.10
  nginx                           1.28.0-6ubuntu1.4
  nginx-core                      1.28.0-6ubuntu1.4
  nginx-extras                    1.28.0-6ubuntu1.4
  nginx-full                      1.28.0-6ubuntu1.4
  nginx-light                     1.28.0-6ubuntu1.4

Ubuntu 24.04 LTS
  nginx                           1.24.0-2ubuntu7.9
  nginx-core                      1.24.0-2ubuntu7.9
  nginx-extras                    1.24.0-2ubuntu7.9
  nginx-full                      1.24.0-2ubuntu7.9
  nginx-light                     1.24.0-2ubuntu7.9

Ubuntu 22.04 LTS
  nginx                           1.18.0-6ubuntu14.12
  nginx-core                      1.18.0-6ubuntu14.12
  nginx-extras                    1.18.0-6ubuntu14.12
  nginx-full                      1.18.0-6ubuntu14.12
  nginx-light                     1.18.0-6ubuntu14.12

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