CVE-2026-42055

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

• f5 dos (>= 4.3.0 <= 4.7.0) • f5 dos 4.9.0 • f5 nginx gateway fabric (>= 1.3.0 <= 1.6.2) • f5 nginx gateway fabric (>= 2.0.0 <= 2.6.3) • f5 nginx ingress controller (>= 3.5.0 <= 3.7.2) • f5 nginx ingress controller (>= 4.0.0 <= 4.0.1) • f5 nginx ingress controller (>= 5.0.0 <= 5.5.0) • f5 nginx instance manager (>= 2.17.0 <= 2.22.0) • f5 nginx open source (>= 1.0.0 <= 1.30.2) • f5 nginx open source (>= 1.31.0 <= 1.31.1) • f5 nginx plus (>= 37.0.0.1 < 37.0.2.1) • f5 nginx plus (>= r33 < r36) • f5 nginx plus r36 • f5 waf (>= 4.10.0 <= 4.16.0) • f5 waf (>= 5.2.0 <= 5.8.0) • f5 waf (>= 5.9.0 <= 5.13.1) • redhat discovery • redhat hardened images • redhat update infrastructure (>= 5.0 < 5.2) • redhat enterprise linux 8.0 • redhat enterprise linux 9.0 • redhat enterprise linux 10.0