PatchTheCVECVE-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
CVE-2026-61511 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 e
Why this priority
- Critical severity
- EPSS top 7%: very likely to be exploited
- Public exploit reference
- CISA SSVC: automatable with total technical impact
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 5.6% (top 7%) |
| CISA exploited list | No |
| Weakness | CWE-95 |
| Published | 2026-07-27 |
| Last modified | 2026-10-14 |
Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: tc4dy/CVE-2026-61511-PoC-Exploit (6 stars)
- GitHub PoC: puj790201-lab/cve-2026-61511 (3 stars)
- GitHub PoC: HORKimhab/CVE-2026-61511 (0 stars)
- Write-up: karmainsecurity.com/KIS-2026-13
- Nuclei scan template: vBulletin 6.x - Remote Code Execution
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-61511?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-61511 being exploited?
CVE-2026-61511 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-61511 affect?
CVE-2026-61511 affects affected software. Severity is critical (CVSS 9.8). 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
How urgent is CVE-2026-61511?
Priority 71/100. Critical severity; EPSS top 7%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action