High · published July 15, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| f5/nginx_gateway_fabric | ≥ 1.3.0, ≤ 1.6.2 | — |
| f5/nginx_gateway_fabric | ≥ 2.0.0, < 2.6.7 | 2.6.7 |
| f5/nginx_ingress_controller | ≥ 3.5.0, ≤ 3.7.2 | — |
| f5/nginx_ingress_controller | ≥ 5.0.0, < 5.5.3 | 5.5.3 |
| f5/nginx_ingress_controller | ≥ 2026-lts-r1, < 2026-lts-r4 | 2026-lts-r4 |
| f5/nginx_ingress_controller | all versions | — |
| f5/nginx_ingress_controller | all versions | — |
| f5/nginx_plus | ≥ 37.0.0.1, < 37.0.3.1 | 37.0.3.1 |
| f5/nginx_plus | ≥ r33, < r36 | r36 |
| f5/nginx_plus | all versions | — |
| f5/nginx_plus | all versions | — |
| f5/nginx_plus | all versions | — |
| f5/nginx_plus | all versions | — |
| f5/nginx_plus | all versions | — |
| f5/nginx_plus | all versions | — |
| f5/nginx_plus | all versions | — |
| f5/waf | ≥ 4.11.0, ≤ 4.16.0 | — |
| f5/waf | ≥ 5.2.0, ≤ 5.8.0 | — |
| f5/waf | ≥ 5.9.0, < 5.13.4 | 5.13.4 |