Authentication Bypass by Spoofing in NGINX Plus and NGINX Open Source - CVE-2026-40460

Vulnerability identifier: #VU131378

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-40460

CWE-ID: CWE-290

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to bypass authorization or cause a denial of service.

The vulnerability exists due to authentication bypass by spoofing in the ngx_quic_module module when handling HTTP/3 QUIC traffic. A remote attacker can spoof their source IP address to bypass authorization or cause a denial of service.

There is no control plane exposure; this is a data plane issue only.

NGINX Plus
NGINX Open Source
Debian Linux
Ubuntu
Anolis OS
Fedora
nginx-mod-js-challenge
nginx-mod-vts
nginx-mod-fancyindex
nginx-mod-headers-more
nginx-mod-brotli
nginx-mod-modsecurity
nginx-mod-naxsi
nginx (Ubuntu package)
nginx (Debian package)
nginx
nginx-mod-devel
nginx-mod-http-image-filter
nginx-mod-http-perl
nginx-mod-http-xslt-filter
nginx-mod-mail
nginx-mod-stream
nginx-all-modules
nginx-doc
nginx-filesystem
nginx-core

Install security update from vendor's website.

NGINX Plus - addressed in versions R32 P6, R36 P4
NGINX Open Source - update to 1.30.1
nginx-mod-js-challenge - update to 0^20230517.gitda6852d-7.fc44
nginx-mod-vts - addressed in versions 0.2.4-9.fc42, 0.2.4-9.fc43, 0.2.4-9.fc44
nginx-mod-fancyindex - addressed in versions 0.6.0-4.fc42, 0.6.0-4.fc43, 0.6.0-4.fc44
nginx-mod-headers-more - addressed in versions 0.39-9.fc42, 0.39-9.fc43, 0.39-9.fc44
nginx-mod-brotli - addressed in versions 1.0.0~rc-9.fc42, 1.0.0~rc-9.fc43, 1.0.0~rc-9.fc44
nginx-mod-modsecurity - addressed in versions 1.0.4-10.fc42, 1.0.4-10.fc43, 1.0.4-10.fc44
nginx-mod-naxsi - addressed in versions 1.6-17.fc42, 1.6-17.fc43, 1.6-17.fc44
nginx (Ubuntu package) - addressed in versions 1.18.0-6ubuntu14.12, 1.24.0-2ubuntu7.9, 1.28.0-6ubuntu1.4, 1.28.3-2ubuntu1.2
nginx (Debian package) - addressed in versions 1.22.1-9+deb12u7, 1.26.3-3+deb13u5
nginx - addressed in versions 1.30.1-1.fc42, 1.30.1-1.fc43, 1.30.1-1.fc44
nginx-mod-devel - update to 1.30.2-1
nginx-mod-http-image-filter - update to 1.30.2-1
nginx-mod-http-perl - update to 1.30.2-1
nginx-mod-http-xslt-filter - update to 1.30.2-1
nginx-mod-mail - update to 1.30.2-1
nginx-mod-stream - update to 1.30.2-1
nginx-all-modules - update to 1.30.2-1
nginx-doc - update to 1.30.2-1
nginx-filesystem - update to 1.30.2-1
nginx-core - update to 1.30.2-1
nginx - update to 1.30.2-1

• https://my.f5.com/manage/s/article/K000161068

• Multiple vulnerabilities in NGINX Open Source and NGINX Plus
• Fedora 44 update for nginx, nginx-mod-brotli, nginx-mod-fancyindex, nginx-mod-headers-more, nginx-mod-js-challenge, nginx-mod-modsecurity, nginx-mod-naxsi, nginx-mod-vts
• Fedora 43 update for nginx, nginx-mod-brotli, nginx-mod-fancyindex, nginx-mod-headers-more, nginx-mod-modsecurity, nginx-mod-naxsi, nginx-mod-vts
• Fedora 42 update for nginx, nginx-mod-brotli, nginx-mod-fancyindex, nginx-mod-headers-more, nginx-mod-modsecurity, nginx-mod-naxsi, nginx-mod-vts
• Debian update for nginx
• Anolis OS update for nginx
• Ubuntu update for nginx