CVE-2026-42530

NGINX Open-Source ngx_http_v3_module vulnerability

State: Published
Severity: 9.2 Critical
Published: Jun 17, 2026
Updated: Jul 16, 2026
Reserved: Jun 2, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	9.2 Critical	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	f5
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	f5
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	redhat-SADP

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
NGINX Open SourceF5	1.31.0 to before 1.31.2Affected

References

https://my.f5.com/manage/s/article/K000161616vendor-advisory
https://access.redhat.com/security/cve/CVE-2026-42530vdb-entry
RHBZ#2489872issue-tracking
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.json
https://access.redhat.com/errata/RHSA-2026:20351vendor-advisory

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