CVE-2026-42533
HIGH
CVSS 8.1
CVE-2026-42533 — HIGH
Qu'est-ce que c'est ?
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. Impact: This 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. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Technologies affectées
Non précisé par la fiche NVD.
Recommandation
Vérifie la disponibilité d'un correctif pour la technologie concernée et applique-le dès que possible. Consulte la fiche NVD pour les références officielles du fournisseur.
Exploits publics connus (8)
CVE-2026-42533: pre-auth nginx heap overflow and info leak from PCRE capture clobbering in the map/script engine, chained to RCE.
nginx heap buffer overflow PoC — CVE-2026-42533 pre-auth RCE via two-pass capture clobbering. Crash confirmed on Ubuntu 24.04.
CVE-2026-42533 Nginx
Vulnerabilidad en NGINX
Tracking the nginx CVE-2026-42533 map/regex capture-clobbering heap overflow
An isolated Vagrant testbed designed to simulate a complete attack chain: Initial access via the Nginx heap buffer overflow (CVE-2026-42533)...
Defensive NGINX CVE-2026-42533 map regex risk audit with config scanner, Splunk/Defender notes, and lab evidence.
Static config scanner that flags nginx configs vulnerable to the complex_value two-pass capture-clobbering bug (regex map + regex capture →...
Usage responsable : ces liens pointent vers des dépôts publics GitHub à but éducatif ou de test d'intrusion autorisé. N'utilise ces PoC que sur des systèmes que tu es autorisé à tester.