Critical severity · published Jul 27, 2026
CVE-2026-61511
vBulletin < 6.2.2 Eval Injection RCE via vb5/template/runtime.php
9.8
CVSS
5.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)5.6% · higher than 93% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
VB
vBulletin · vBulletin
5.0.0 through 5.7.5; 6.0.0 through 6.2.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-61511
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-61511
technical-description
https://karmainsecurity.com/KIS-2026-13
technical-description
https://ssd-disclosure.com/vbulletin-runtime-template-runmaths-preauth-rce/
forum.vbulletin.com
https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4509358-security-patch-released-for-vbulletin-6-2-1-6-2-0-and-6-1-6
forum.vbulletin.com
https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4509404-vbulletin-6-2-2-is-available
third-party-advisory
https://www.vulncheck.com/advisories/vbulletin-eval-injection-rce-via-vb5-template-runtime-php
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