# 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.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Jul 2026
- **Updated:** 14 Oct 2026
- **Also known as:** GHSA-43hg-f3wj-j2m6

## 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 (Improper Neutralization of Directives in Dynamically Evaluated Code)

## 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.

## 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:

- CVE-2026-61511 – vBulletin Pre-Auth RCE (CVSS 9.8). Vuln 5.x/6.x (unpatched). Multi-exploit via Endpoint Pool, AJAX, PHPFuck WAF bypass. Full toolkit: reverse shell, proxy, persistence, webshell, database operations, firewall control, log management, mass scanning. 2 versions: multi-exploit & safe-check. Python 3.8+ Use Ethically, Stay Legal.  (github_poc): https://github.com/tc4dy/CVE-2026-61511-PoC-Exploit
- cve-2026-61511 (github_poc): https://github.com/puj790201-lab/cve-2026-61511
- CVE-2026-61511 - Draft or Todo (github_poc): https://github.com/HORKimhab/CVE-2026-61511
- 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 (github_poc): https://github.com/codeb0ssx/Ultimate-CVE-2026-61511
- https://github.com/shootcannon/CVE-2026-61511 (github_poc): https://github.com/shootcannon/CVE-2026-61511
- vBulletin 6.x - Remote Code Execution (nuclei): http/cves/2026/CVE-2026-61511.yaml

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61511 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61511 exists.

Affected product: vBulletin. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-61511/ (Markdown: https://insights.sbomify.com/CVE-2026-61511/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61511
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61511
- OSV: https://osv.dev/vulnerability/CVE-2026-61511

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61511/
Summaries are generated and may contain mistakes; the official description above is the record.