CVE-2026-61511
9.8
CRITICAL · CVSS 3.1 · EPSS 5.6% (pctl 93)
In your normal cycle
Critical by CVSS (9.8), but no sign of active exploitation.
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.
Scoring
| CVSS | 9.8 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 5.61% — more likely to be exploited than 93% of all CVEs |
| Weakness | CWE-95 |
| On CISA KEV | no |
| Public exploit | none known |
| Published | 2026-07-27 |
| Last modified | 2026-08-07 |
References
- 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
- https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4509404-vbulletin-6-2-2-is-available
- https://karmainsecurity.com/KIS-2026-13
- https://ssd-disclosure.com/vbulletin-runtime-template-runmaths-preauth-rce/
- https://www.vulncheck.com/advisories/vbulletin-eval-injection-rce-via-vb5-template-runtime-php
- http://seclists.org/fulldisclosure/2026/Aug/29
→ the Explorer · watch your stack · NVD