Description
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.
CVSS breakdown
Affected products
- F5 / NGINX Gateway Fabric1.3.0 – 1.6.2
- F5 / NGINX Ingress Controller3.5.0 – 3.7.2
- F5 / NGINX Ingress Controller2026-lts-r1 – 2026-lts-r4
- F5 / NGINX Ingress Controller4.0.0 – 4.0.0
- F5 / NGINX Ingress Controller4.0.1 – 4.0.1
- F5 / NGINX Open Source0.9.6 – 1.30.4
- F5 / NGINX Open Source1.31.2 – 1.31.3
- F5 / NGINX Plusr36 – r36
- F5 / NGINX Plusr36 – r36
- F5 / NGINX Plusr36 – r36
- F5 / NGINX Plusr36 – r36
- F5 / NGINX PlusR33 – *
- F5 / NGINX Plus37.0.0.1 – 37.0.3.1
- F5 / NGINX PlusR36 – R36 P7
- F5 / NGINX Plus37.0.0.1 – 37.0.3.1
- F5 / NGINX Plusr36 – r36
- F5 / NGINX Plusr36 – r36
- F5 / NGINX Plusr36 – r36
- F5 / waf4.11.0 – 4.16.0
News coverage
- Critical NGINX Vulnerability Can Crash Workers and May Allow Remote Code ExecutionThe Hacker News · 7/19/2026