CVE Tools
Sign in

CVE-2026-42530

NGINX Open-Source ngx_http_v3_module vulnerability

Published: Jun 17, 2026Updated: Jul 16, 2026 Sources: CVE List NVD BDUCWE-416
8.1HIGH
NVD MITRE
EPSS Score
3.7%
Top 11.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

In plain language

AI Worth attention

CVE-2026-42530 is a high-impact bug in F5 NGINX Open Source when HTTP/3 (QUIC) is enabled, where a crafted network session can crash NGINX and potentially lead to more serious consequences; if you run F5 NGINX Open Source with HTTP/3 enabled, you should act soon.

What to do

  1. Check whether your F5 NGINX Open Source is configured with the HTTP/3 QUIC module (ngx_http_v3_module). 2) Update NGINX Open Source to the patched version your vendor provides (ask your IT/NGINX maintainer to confirm the exact target version). 3) After updating, verify HTTP/3 is still configured as intended and monitor NGINX for restarts or unusual HTTP/3 traffic.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-416

Affected Products

F5
commercial·US
nginx gateway fabricOn-premNetwork Device
Networking Infrastructure / load-balancer-proxy
nginx ingress controllerOn-premNetwork Device
Networking Infrastructure / load-balancer-proxy
nginx instance managerOn-prem
Networking Infrastructure / load-balancer-proxy
NGINX Open SourceOn-premWeb App
Networking Infrastructure / load-balancer-proxy
NGINX Inc.
commercial·USaka nginx, nginx plus, njs
NGINX Gateway Fabric
Networking Infrastructure
NGINX Ingress Controller
Networking Infrastructure
NGINX Instance Manager
Networking Infrastructure
NGINX Open Source
Networking Infrastructure
and 1 more affected products View all →

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-42530?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://my.f5.com/manage/s/article/K000161616
my.f5.com
https://access.redhat.com/errata/RHSA-2026:20351
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-42530
access.redhat.com
and 5 more references View all →
News mentions
6

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-42530 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows