{"id":"CVE-2026-42533","details":"A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. 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\nImpact:\nThis vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.\n\n\n\n\n Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","aliases":["BIT-nginx-2026-42533","BIT-nginx-gateway-2026-42533"],"modified":"2026-10-24T10:30:41.404024020Z","published":"2026-07-15T15:16:33.480Z","related":["ALSA-2026:66542","ALSA-2026:67283","ALSA-2026:67308","ALSA-2026:67314","ALSA-2026:67315","SUSE-SU-2026:23118-1","SUSE-SU-2026:23140-1","SUSE-SU-2026:3448-1","SUSE-SU-2026:3469-1","openSUSE-SU-2026:11295-1","openSUSE-SU-2026:21524-1"],"database_specific":{"unresolved_ranges":[{"cpes":["cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:continuous_releases:*:*:*","cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:long-term_support:*:*:*"],"extracted_events":[{"source":"CPE_RANGE","range":[{"introduced":"3.5.0"},{"last_affected":"3.7.2"},{"introduced":"5.0.0"},{"fixed":"5.5.3"},{"introduced":"2026-lts-r1"},{"fixed":"2026-lts-r4"}]}],"vendor_product":"f5:nginx_ingress_controller"},{"extracted_events":[{"range":[{"introduced":"37.0.0.1"},{"fixed":"37.0.3.1"},{"introduced":"r33"},{"fixed":"r36"}],"source":"CPE_RANGE"}],"vendor_product":"f5:nginx_plus","cpes":["cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*"]},{"vendor_product":"f5:waf","cpes":["cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*"],"extracted_events":[{"range":[{"introduced":"4.11.0"},{"last_affected":"4.16.0"},{"introduced":"5.2.0"},{"last_affected":"5.8.0"},{"introduced":"5.9.0"},{"fixed":"5.13.4"}],"source":"CPE_RANGE"}]},{"cpes":["cpe:2.3:a:f5:nginx_ingress_controller:4.0.0:*:*:*:continuous_releases:*:*:*","cpe:2.3:a:f5:nginx_ingress_controller:4.0.1:*:*:*:continuous_releases:*:*:*"],"extracted_events":[{"range":[{"introduced":"4.0.0"},{"last_affected":"4.0.0"},{"introduced":"4.0.1"},{"last_affected":"4.0.1"}],"source":"CPE_STRING"}],"vendor_product":"f5:nginx_ingress_controller"},{"cpes":["cpe:2.3:a:f5:nginx_plus:r36:-:*:*:*:*:*:*","cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:*","cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:*","cpe:2.3:a:f5:nginx_plus:r36:p3:*:*:*:*:*:*","cpe:2.3:a:f5:nginx_plus:r36:p4:*:*:*:*:*:*","cpe:2.3:a:f5:nginx_plus:r36:p5:*:*:*:*:*:*","cpe:2.3:a:f5:nginx_plus:r36:p6:*:*:*:*:*:*"],"extracted_events":[{"source":"CPE_STRING","range":[{"introduced":"r36-NA"},{"last_affected":"r36-NA"},{"introduced":"r36-p1"},{"last_affected":"r36-p1"},{"introduced":"r36-p2"},{"last_affected":"r36-p2"},{"introduced":"r36-p3"},{"last_affected":"r36-p3"},{"introduced":"r36-p4"},{"last_affected":"r36-p4"},{"introduced":"r36-p5"},{"last_affected":"r36-p5"},{"introduced":"r36-p6"},{"last_affected":"r36-p6"}]}],"vendor_product":"f5:nginx_plus"}]},"references":[{"type":"ADVISORY","url":"https://my.f5.com/manage/s/article/K000162097"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nginx/nginx-gateway-fabric","events":[{"introduced":"3a372747333fb1db372af7cf0b18ed7eef7c91f7"},{"last_affected":"532db6a20b2912fe397211eef9f8d564d46a4bdd"},{"introduced":"7dad8b31e3f0c3eadce36fed8c276e83e6583d24"},{"fixed":"5e34a17a8f7787e90f41d1af91258a556f0795b4"}],"database_specific":{"extracted_events":[{"cpe":"cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*","range":[{"introduced":"1.3.0"},{"last_affected":"1.6.2"}],"source":"CPE_RANGE"},{"cpe":"cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*","range":[{"introduced":"2.0.0"},{"fixed":"2.6.7"}],"source":"CPE_RANGE"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42533.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/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"}]}