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 …
Impact
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
| Vendor | Product | Affected versions |
|---|---|---|
| F5 | Nginx Gateway Fabric | from 1.3.0 through 1.6.2 from 2.0.0 before 2.6.7 |
| F5 | Nginx Ingress Controller | from 3.5.0 through 3.7.2 from 5.0.0 before 5.5.3 from 2026-lts-r1 before 2026-lts-r4 Versions 4.0.0, 4.0.1 |
| F5 | Nginx Plus | from 37.0.0.1 before 37.0.3.1 from r33 before r36 Version r36 |
| F5 | Waf | from 4.11.0 through 4.16.0 from 5.2.0 through 5.8.0 from 5.9.0 before 5.13.4 |