Eval Injection Vulnerability in vBulletin Versions 5.x and 6.x
CVE-2026-61511
Key Information:
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What is CVE-2026-61511?
The vBulletin platform, including versions 5.x up to 5.7.5 and 6.x up to 6.2.1, is susceptible to an eval injection vulnerability found in the vB5_Template_Runtime::runMaths() method. This issue can be leveraged by unauthenticated attackers who submit specially crafted inputs through the pagenav[pagenumber] parameter. By exploiting a flawed regex filter, attackers can utilize phpfuck-style encoding with accepted characters, enabling them to inject and execute arbitrary PHP code via the ajax/render template route without the need for authentication. This vulnerability poses significant risks for the integrity and security of affected vBulletin installations.
Affected Version(s)
vBulletin 5.0.0 <= 5.7.5
vBulletin 5.0.0 <= 5.7.5
vBulletin 6.0.0 <= 6.2.1
Exploit Proof of Concept (PoC)
PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.
News Articles
The Hacker NewsCVE-2026-61511Public Exploit Released for Patched vBulletin Pre-Auth Code Execution Flaw
Public exploit details show how CVE-2026-61511 reaches PHP eval() in unpatched vBulletin forums through a visitor-controlled template value.
2 hours ago
References
CVSS V4
Timeline
- 🟡
Public PoC available
- 👾
Exploit known to exist
- 📰
First article discovered by The Hacker News
Vulnerability published
Vulnerability Reserved