CVE-2026-42945

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewrite directive is followed by a rewrite, if, or set directive and an unnamed Perl-Compatible Regular Expression (PCRE) capture (for example, $1, $2) with a replacement string that includes a question mark (?). An unauthenticated attacker along with conditions beyond its control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap 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 4.8.0 • f5 nginx gateway fabric (>= 1.3.0 <= 1.6.2) • f5 nginx gateway fabric (>= 2.0.0 <= 2.5.1) • 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 <= 5.4.1) • f5 nginx instance manager (>= 2.16.0 <= 2.21.1) • f5 nginx open source (>= 0.6.27 <= 1.30.0) • f5 nginx plus (>= r32 <= r36) • f5 waf (>= 4.9.0 <= 4.16.0) • f5 waf (>= 5.1.0 <= 5.8.0) • f5 waf (>= 5.9.0 <= 5.12.1)