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.
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- Published by NVD
- Last updated by NVD
Affected products
| Product | Versions |
|---|---|
| F5 Nginx Gateway Fabric | from 1.3.0 to 1.6.2; from 2.0.0 to before 2.6.7 |
| F5 Nginx Ingress Controller | from 2026-lts-r1 to before 2026-lts-r4; from 3.5.0 to 3.7.2; 4.0.0 only; 4.0.1 only; from 5.0.0 to before 5.5.3 |
| F5 Nginx Plus | from 37.0.0.1 to before 37.0.3.1; from an unspecified version to before an unspecified version; version not stated; version not stated; version not stated; version not stated and 3 more |
| F5 Waf | from 4.11.0 to 4.16.0; from 5.2.0 to 5.8.0; from 5.9.0 to before 5.13.4 |
Sources: NVD and CISA known exploited vulnerabilities catalogue.