CVE-2026-42945

A flaw was found in NGINX, specifically within the ngx_http_rewrite_module. An unauthenticated attacker can exploit this vulnerability by sending crafted HTTP requests under specific rewrite configurations. This can lead to a heap buffer overflow in the NGINX worker process, which may result in arbitrary code execution if Address Space Layout Randomization (ASLR), a security technique to prevent exploitation, is disabled. Otherwise, this flaw causes a denial of service due to a restart of the NGINX worker process.

Critical: This flaw in NGINX's ngx_http_rewrite_module can lead to arbitrary code execution due to a heap buffer overflow if Address Space Layout Randomization (ASLR) is disabled, or a denial of service otherwise. Exploitation requires specific, non-default NGINX rewrite configurations involving unnamed PCRE captures and a question mark in the replacement string.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.