9.8
CRITICAL CVSS 3.1
CVE-2026-61511
vBulletin < 6.2.2 Eval Injection RCE via vb5/template/runtime.php
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.

INFO

Published Date :

July 27, 2026, 2:16 p.m.

Last Modified :

July 27, 2026, 3:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-61511 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 CRITICAL [email protected]
CVSS 4.0 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 CRITICAL [email protected]
Solution
Update vBulletin to patch eval injection vulnerability allowing remote code execution.
  • Update vBulletin to version 5.7.6 or 6.2.2.
  • Apply vendor patches if available.
  • Sanitize user input for pagenav[pagenumber].
  • Restrict access to ajax/render endpoint.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-61511 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-61511 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-61511 vulnerability anywhere in the article.

  • The Hacker News
Public Exploit Released for Patched vBulletin Pre-Auth Code Execution Flaw

Public exploit details released on July 27 show how an unauthenticated request can reach PHP's eval() function inside vBulletin and execute code on an unpatched forum server. The attack requires no ac ... Read more

Published Date: Jul 27, 2026 (1 hour, 51 minutes ago)

The following table lists the changes that have been made to the CVE-2026-61511 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 27, 2026

    Action Type Old Value New Value
    Added SSVC {'id': 'CVE-2026-61511', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-27T13:53:15.288364Z'}
  • New CVE Received by [email protected]

    Jul. 27, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'vBulletin', 'product': 'vBulletin', 'versions': [{'status': 'affected', 'version': '5.0.0', 'versionType': 'semver', 'lessThanOrEqual': '5.7.5'}, {'status': 'affected', 'version': '6.0.0', 'versionType': 'semver', 'lessThanOrEqual': '6.2.1'}, {'status': 'unaffected', 'version': '6.2.2', 'versionType': 'semver'}], 'defaultStatus': 'affected'}]
    Added 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.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Added CWE CWE-95
    Added Reference 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
    Added Reference https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4509404-vbulletin-6-2-2-is-available
    Added Reference https://karmainsecurity.com/KIS-2026-13
    Added Reference https://ssd-disclosure.com/vbulletin-runtime-template-runmaths-preauth-rce/
    Added Reference https://www.vulncheck.com/advisories/vbulletin-eval-injection-rce-via-vb5-template-runtime-php
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.