CVE-2026-42530
NGINX Open-Source ngx_http_v3_module vulnerability
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.
INFO
Published Date :
June 17, 2026, 3:16 p.m.
Last Modified :
July 2, 2026, 8:03 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-42530
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 9dacffd4-cb11-413f-8451-fbbfd4ddc0ab | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | ||||
| CVSS 4.0 | CRITICAL | 9dacffd4-cb11-413f-8451-fbbfd4ddc0ab | ||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update NGINX to a fixed version.
- Disable the HTTP/3 QUIC module if updating is not possible.
Public PoC/Exploit Available at Github
CVE-2026-42530 has a 8 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42530.
| URL | Resource |
|---|---|
| https://my.f5.com/manage/s/article/K000161616 | Vendor Advisory |
| https://access.redhat.com/security/cve/CVE-2026-42530 | Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2489872 | Third Party Advisory |
| https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.json | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42530 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42530
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Non-destructive vulnerability scanner for NGINX HTTP/3 (ngx_http_v3_module). It ONLY performs a safe probe: opens an HTTP/3 (QUIC) connection, sends a single HEAD request and inspects the `Server` response header. It NEVER attempts to reopen a QPACK encoder stream or trigger the use-after-free.
Python
CVE-2026-42530
Python
Scanner PoC for CVE-2026-42530 -- nginx 1.31.0-1.31.1 HTTP/3 QPACK encoder stream Use-After-Free (CVSS 9.2)
Python
CVE-2026-42530 - Draft
Web Application Firewall for nginx
CMake C Shell C++ HTML PHP Perl Python
Tracking CVEs discovered by AI systems — Anthropic, OpenAI, Google Big Sleep, Microsoft MDASH, DepthFirst
WNMP One‑Click Stack | WebDAV · Nginx · PHP · MariaDB · Kernel Tuning
Shell HTML
A collection of Vulnerability Research and Reverse Engineering writeups.
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42530 vulnerability anywhere in the article.
-
The Hacker News
F5 Patches Two Critical NGINX Open Source Flaws Enabling Remote Code Execution
Ravie LakshmananJun 18, 2026Vulnerability / Cloud Security F5 has released security updates to address two critical security flaws in NGINX Open Source that could be exploited to achieve code execut ... Read more
The following table lists the changes that have been made to the
CVE-2026-42530 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 02, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* versions from (including) 1.3.0 up to (including) 1.6.2 *cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:* versions from (including) 3.5.0 up to (including) 3.7.2 *cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:* versions from (including) 2.17.0 up to (including) 2.22.0 *cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* versions from (including) 2.0.0 up to (excluding) 2.6.4 *cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:* versions from (including) 5.0.0 up to (excluding) 5.5.1 *cpe:2.3:a:f5:nginx_ingress_controller:4.0.0:*:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_ingress_controller:4.0.1:*:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* versions from (including) 1.31.0 up to (excluding) 1.31.2 Added Reference Type F5 Networks: https://my.f5.com/manage/s/article/K000161616 Types: Vendor Advisory Added Reference Type redhat-SADP: https://access.redhat.com/security/cve/CVE-2026-42530 Types: Third Party Advisory Added Reference Type redhat-SADP: https://bugzilla.redhat.com/show_bug.cgi?id=2489872 Types: Third Party Advisory Added Reference Type redhat-SADP: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.json Types: Third Party Advisory -
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:hummingbird:1'], 'vendor': 'Red Hat', 'product': 'Red Hat Hardened Images', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:insights_proxy:1'], 'vendor': 'Red Hat', 'product': 'Red Hat Lightspeed proxy 1', 'defaultStatus': 'unaffected'}] Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-416 Added Reference https://access.redhat.com/security/cve/CVE-2026-42530 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2489872 Added Reference https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.json -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 18, 2026
Action Type Old Value New Value Changed SSVC {'id': 'CVE-2026-42530', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-17T15:43:30.346337Z'} {'id': 'CVE-2026-42530', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-17T00:00:00+00:00'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-42530', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-17T15:43:30.346337Z'} -
New CVE Received by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'F5', 'modules': ['ngx_http_v3_module'], 'product': 'NGINX Open Source', 'versions': [{'status': 'affected', 'version': '1.31.0', 'lessThan': '1.31.2', 'versionType': 'custom'}], 'defaultStatus': 'unknown'}] Added 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. Added CVSS V4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-416 Added Reference https://my.f5.com/manage/s/article/K000161616