CVE-2026-9256

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their 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 nginx open source (>= 0.1.17 <= 0.9.7) • f5 nginx open source (>= 1.0.0 < 1.30.2) • f5 nginx open source 1.31.0 • f5 nginx plus (>= r33 < r36) • f5 nginx plus 37.0.0.1 • f5 nginx plus r32 • f5 nginx plus r36 • 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 < 2.6.2) • 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 < 5.4.3) • f5 nginx instance manager (>= 2.17.0 < 2.22.1) • f5 waf (>= 4.10.0 <= 4.16.0) • f5 waf (>= 5.2.0 <= 5.8.0) • f5 waf (>= 5.9.0 <= 5.13.0) • redhat discovery • redhat hardened images • redhat update infrastructure (>= 5.0 < 5.2) • debian debian linux 11.0 • redhat enterprise linux 8.0 • redhat enterprise linux 9.0 • redhat enterprise linux 10.0