CVE-2026-42530

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

Nginx Open Source, Nginx

f5 Nginx Gateway Fabric

≤ 1.6.2, 2.6.4

f5 Nginx Ingress Controller

≤ 3.7.2, 5.5.1, 4.0.0, 4.0.1

f5 Nginx Instance Manager

≤ 2.22.0

f5 Nginx Open Source

< 1.31.2

Fix

Available

CVSS 4.0

9.2 CRITICAL

CVSS 3.1

8.1 HIGH

EPSS

3.7% (89th percentile)

Weakness

CWE-416

NVD status

Modified

Published

2026-06-17