USN-8354-1: nginx vulnerabilities

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)