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[USN-8354-1] nginx vulnerabilities

Posted on 01 June 2026
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-8354-1
June 01, 2026

nginx vulnerabilities
==========================================================================
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:

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-2026-42934)

It was discovered that nginx did not properly process certain SCGI and
uWSGI responses. An attacker able to perform a machine-in-the-middle attack
could possibly use this issue to obtain sensitive information or cause
nginx to crash, resulting in a denial of service. (CVE-2026-42946)

It was discovered that nginx incorrectly handled certain rewrite rules in
the ngx_http_rewrite_module module. A remote attacker could use this issue
to cause nginx to crash, resulting in a denial of service, or possibly
execute arbitrary code. (CVE-2026-9256)

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.

References:
https://ubuntu.com/security/notices/USN-8354-1
CVE-2026-40460, CVE-2026-40701, CVE-2026-42934, CVE-2026-42946,
CVE-2026-9256

Package Information:
https://launchpad.net/ubuntu/+source/nginx/1.28.3-2ubuntu1.2
https://launchpad.net/ubuntu/+source/nginx/1.28.0-6ubuntu1.4
https://launchpad.net/ubuntu/+source/nginx/1.24.0-2ubuntu7.9
https://launchpad.net/ubuntu/+source/nginx/1.18.0-6ubuntu14.12

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