What’s Vulnerable › Vulnerabilities

CVE-2026-42055: NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability

Description

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.

Affected products

How to fix

Upgrade to a fixed version: F5 NGINX Plus 37.0.2.1, r36; RedHat Update Infrastructure 5.2. Check the vendor advisory for mitigations.

References

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