CVE-2026-90439: F5 Nginx Open Source

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_v3_module module. When using HTTP/3 with OpenSSL versions <= OpenSSL 3.5.0 under certain configurations, a limited heap buffer overflow could happen while processing a TLS handshake. This can happen in a non-deterministic manner that is beyond the attacker's control. This may cause a heap buffer overflow in the NGINX worker process leading to a restart and/or limited data corruption. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or limited data corruption. 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

• F5 Nginx Open Source: from 1.29.2, before 1.31.6 (fixed in 1.31.6); from 1.30.4, before 1.30.5 (fixed in 1.30.5)
• F5 Nginx Plus: from 37.1.0.1, before 37.1.1.2 (fixed in 37.1.1.2); from 37.0.0.1, before 37.0.6.2 (fixed in 37.0.6.2)

Published 2026-09-15. Last modified 2026-09-18.