{"id":"CVE-2026-42533","aliases":["BIT-nginx-2026-42533","BIT-nginx-gateway-2026-42533"],"url":"https://o3.security/vulnerability/CVE-2026-42533","summary":null,"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.","published":"2026-07-15T15:16:33.480Z","modified":"2026-09-16T13:56:33.950067694Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":2,"affectedPackages":[],"fix":null,"references":[{"type":"ADVISORY","url":"https://my.f5.com/manage/s/article/K000162097"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-16T13:56:33.950067694Z"}}