CVE-2026-61511 vBulletin < 6.2.2 Eval Injection RCE via vb5/template/runtime.php
Unauthenticated attackers can execute arbitrary PHP code in vBulletin via crafted input in the template runtime, risking full server compromise.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-61511?
CVE-2026-61511 is a critical code injection vulnerability in vBulletin, published on 27 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
vBulletin 5.x through 5.7.5 and 6.x through 6.2.1 contains an eval injection vulnerability in the vB5_Template_Runtime::runMaths() method within the template runtime that allows unauthenticated remote attackers to execute arbitrary PHP code by supplying crafted input through the pagenav[pagenumber] parameter. Attackers can exploit the insufficiently restrictive regex filter by using phpfuck-style encoding with permitted characters to inject and execute arbitrary PHP code via the unauthenticated ajax/render template route without any authentication.
Weakness: CWE-95
Which versions are affected by CVE-2026-61511?
How do I fix CVE-2026-61511?
No fix has been published for CVE-2026-61511 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-61511 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61511 exists.
Public exploit code: 1 Nuclei template and 5 proofs of concept on GitHub.
Sources
Also known as GHSA-43hg-f3wj-j2m6.