Tracker / CVE-2026-42533
CVE-2026-42533
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.
Affected products and versions
| f5 | nginx_gateway_fabric · 1.3.0 → 1.6.2 |
|---|---|
| f5 | nginx_gateway_fabric · 2.0.0 → 2.6.7 |
| f5 | nginx_ingress_controller |
| f5 | nginx_ingress_controller · 2026-lts-r1 → 2026-lts-r4 |
| f5 | nginx_ingress_controller · 3.5.0 → 3.7.2 |
| f5 | nginx_ingress_controller · 5.0.0 → 5.5.3 |
| f5 | nginx_plus |
| f5 | nginx_plus · 37.0.0.1 → 37.0.3.1 |
| f5 | nginx_plus · r33 → r36 |
| f5 | waf · 4.11.0 → 4.16.0 |
| f5 | waf · 5.2.0 → 5.8.0 |
| f5 | waf · 5.9.0 → 5.13.4 |