How severe is CVE-2026-61511?

CVE-2026-61511 has a CVSS 3.1 base score of 9.8 (CRITICAL). EPSS estimates a 5.6% probability of exploitation in the next 30 days.

CVE-2026-61511: vBulletin < 6.2.2 Eval Injection RCE via

Q: What is 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 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.

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.

Severity

CVSS 4.0 · CNA9.3 CRITICAL

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

CVSS 3.1 · CNA9.8 CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC · CISA-ADP

Exploitationnone

Automatableyes

Technical impacttotal

Affected Products

Vendor	Product	Affected versions
vBulletin	vBulletin	5.0.0 to 5.7.5 6.0.0 to 6.2.1 6.2.2 (unaffected)

References

6 Links

Exploits & PoCs

Third-party advisories

https://www.vulncheck.com/advisories/vbulletin-eval-injection-rce-via-vb5-template-runtime-php

Other references

Record Details

Published

2026-07-27

Last updated

2026-08-07

Assigner (CNA)

VulnCheck

Credited to

Egidio Romano

Related Tool Categories

Tool categories that test for or protect against this vulnerability class.

CWE-95 · Eval Injection

Application Security Tools Penetration Testing Tools

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.