{"id":"BIT-nginx-gateway-2026-9256","summary":"NGINX ngx_http_rewrite_module vulnerability","details":"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. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","aliases":["BIT-nginx-2026-9256","CVE-2026-9256"],"modified":"2026-07-06T08:00:58.400922906Z","published":"2026-06-01T11:47:02.728Z","database_specific":{"cpes":["cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*"],"severity":"Critical"},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/05/22/14"},{"type":"WEB","url":"https://my.f5.com/manage/s/article/K000161377"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9256"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2026/06/msg00023.html"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:20351"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:28212"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:28921"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:28973"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:29151"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:29874"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:33313"},{"type":"WEB","url":"https://access.redhat.com/security/cve/CVE-2026-9256"},{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2480746"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9256.json"}],"affected":[{"package":{"name":"nginx-gateway","ecosystem":"Bitnami","purl":"pkg:bitnami/nginx-gateway"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.1.17"},{"fixed":"2.2.1"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/nginx-gateway/BIT-nginx-gateway-2026-9256.json"},"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}],"schema_version":"1.7.5"}