MSRXCVE-2026-93479
CVE-2026-93479
NGINX map directive and regex matching vulnerability
CVSS 4.0 · CNA · f5.com
chance of exploitation in the next 30 days (EPSS; higher than 68% of CVEs)
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format 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.
Scores
Affected products
- F5 NGINX Plus: 37.1.0 to < 37.1.0.1; 37.0.0 to < 37.0.5.1; R36 to < *; R35 to < *; R34 to < *; R33 to < *
- F5 NGINX Open Source: 1.31.2 to < 1.31.7; 1.30.0 to < 1.30.6
Weakness: CWE-122
1 references (advisories, patches, write-ups)
Sources: NVD, CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.