CVE-2026-42530: F5 Nginx Gateway Fabric

High severity, CVSS 8.1. EPSS: 1.1% chance of exploitation in the next 30 days.

NGINX Open Source has a vulnerability in the ngx_http_v3_module module. When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote unauthenticated attacker along with conditions beyond their control can use a specially crafted HTTP/3 session to reopen a QPACK encoder stream. This may cause a Use-after-Free 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. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products

• F5 Nginx Gateway Fabric: from 1.3.0, up to and including 1.6.2; from 2.0.0, before 2.6.4 (fixed in 2.6.4)
• F5 Nginx Ingress Controller: from 3.5.0, up to and including 3.7.2; from 5.0.0, before 5.5.1 (fixed in 5.5.1); version 4.0.0 only; version 4.0.1 only
• F5 Nginx Instance Manager: from 2.17.0, up to and including 2.22.0
• F5 Nginx Open Source: from 1.31.0, before 1.31.2 (fixed in 1.31.2)

Published 2026-06-17. Last modified 2026-07-16.