CVE-2026-42530CWE-416

NGINX Open-Source ngx_http_v3_module vulnerability

Critical · published June 17, 2026

CVSS v4.0
9.2
EPSS
1%
Percentile
73.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
9.2 · CRITICAL
Vector
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EPSS
0.01478 · 73.7th percentile
Weakness
CWE-416 · Use After Free
Published
2026-06-17T14:04Z
EPSS history
Timeline
  • 17 JUN 14:04Z
    NGINX Open-Source ngx_http_v3_module vulnerability
    cvelistv5