{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42055","assignerOrgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","state":"PUBLISHED","assignerShortName":"f5","dateReserved":"2026-06-02T21:45:04.818Z","datePublished":"2026-06-17T14:04:32.520Z","dateUpdated":"2026-07-28T12:04:38.243Z"},"containers":{"cna":{"affected":[{"defaultStatus":"unknown","modules":["ngx_http_proxy_v2_module","ngx_http_grpc_module"],"product":"NGINX Open Source","vendor":"F5","versions":[{"lessThan":"1.31.2","status":"affected","version":"1.13.10","versionType":"custom"},{"lessThan":"1.30.3","status":"affected","version":"1.30.2","versionType":"custom"}]},{"defaultStatus":"unaffected","modules":["ngx_http_proxy_v2_module","ngx_http_grpc_module"],"product":"NGINX Plus","vendor":"F5","versions":[{"lessThan":"37.0.2.1","status":"affected","version":"37.0","versionType":"custom"},{"lessThan":"R36 P6","status":"affected","version":"R36","versionType":"custom"}]}],"credits":[{"lang":"en","type":"reporter","value":"\"F5 acknowledges Mufeed VH of Winfunc Research, Trung Nguyen (@everping) of CyStack, Feng Xue and XGPT of ThreatBook, Hcamael and 章鱼哥 of aipyapp, and Zhen Yan (AntAISecurityLab) for bringing this issue to our attention and following the highest standards of coordinated disclosure.\""}],"datePublic":"2026-06-17T14:00:00.000Z","descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<span style=\"background-color: rgb(255, 255, 255);\">NGINX Plus and NGINX Open Source have a vulnerability in the </span><strong>ngx_http_proxy_v2_module</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;and </span><strong>ngx_http_grpc_module</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;modules. This vulnerability exists when the </span><strong>proxy_http_version to 2</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;or </span><strong>grpc_pass</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;directives are used to proxy HTTP/2 traffic, the </span><strong>ignore_invalid_headers</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;directive is set to off, and the </span><strong>large_client_header_buffers</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;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.</span> \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."}],"value":"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. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not 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When NGINX is configured to proxy HTTP/2 traffic using the ngx_http_proxy_v2_module or ngx_http_grpc_module with specific settings, a remote, unauthenticated attacker can send specially crafted large headers. This can trigger a heap-based buffer overflow, leading to a restart of the NGINX worker process and a Denial of Service (DoS). 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