CVE-2026-42530

NGINX Open-Source ngx_http_v3_module vulnerability

HIGH
8.1
CVSS Score
Published: June 17, 2026 at 02:04 PM UTC
Updated: October 26, 2026 at 12:10 PM UTC
4 products affected across 1 vendorNGINX Open SourceNGINX Ingress ControllerNGINX Gateway Fabric

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Severity
HIGH8.1
Exploit prediction
EPSS 6%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.3.0 ≤ v ≤ 1.6.22.0.0 ≤ v < 2.6.4
Affected range stops below 2.6.4, so it looks safe — our inference, not a vendor statement
3.5.0 ≤ v ≤ 3.7.25.0.0 ≤ v < 5.5.14.0.04.0.1
Affected range stops below 5.5.1, so it looks safe — our inference, not a vendor statement
2.17.0 ≤ v ≤ 2.22.0
1.31.0 ≤ v < 1.31.21.31.0
Affected range stops below 1.31.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (5)

Vendor Advisory
Source: cverecord
https://my.f5.com/manage/s/article/K000161616
Third Party Advisory
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-42530
Third Party Advisory
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=2489872
Third Party Advisory
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.json
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:20351

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHf5
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-416

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