CVE-2026-42530 NGINX Open-Source ngx_http_v3_module vulnerability
Remote attackers can trigger a use-after-free in NGINX HTTP/3 module causing crashes or code execution if ASLR is bypassed.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42530?
CVE-2026-42530 is a critical use after free vulnerability in F5 NGINX Open Source, published on 17 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-416
Which versions are affected by CVE-2026-42530?
2 open source packages ship an affected version, including nginx and nginx-gateway. It affects 4 products.
| Package | Affected | Fixed in |
|---|---|---|
nginx Bitnami | From 1.31.0 | 1.31.2 |
nginx-gateway Bitnami | From 1.31.0 | 1.31.2 |
Products include F5 Nginx Gateway Fabric, F5 Nginx Ingress Controller, F5 Nginx Instance Manager, F5 Nginx Open Source.
How do I fix CVE-2026-42530?
Upgrade nginx to 1.31.2 or later.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-42530 being exploited?
There is no known exploitation of CVE-2026-42530 in the wild and no public exploit code.
Public exploit code: 3 proofs of concept on GitHub.
Other vulnerabilities in F5 NGINX Open Source
Sources
Also known as BIT-nginx-2026-42530, BIT-nginx-gateway-2026-42530, GHSA-5mcp-3252-f5vr, MINI-4mcp-m74h-7cw4.