What is the CVSS score of CVE-2026-61511?

CVE-2026-61511 has a CVSS 4.0 base score of 9.3 (Critical). CVSS vector: 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. EPSS exploitation probability: 1.3%.

Is there a public PoC exploit available for CVE-2026-61511?

Yes, a public proof-of-concept exploit is available for CVE-2026-61511. Prioritise patching immediately. EPSS: 1.3%.

Vbulletin CVE-2026-61511

EUVD-2026-49312 CRITICAL

Eval Injection (CWE-95)

2026-07-27 VulnCheck

GHSA-43hg-f3wj-j2m6

PHP RCE Code Injection Vbulletin

9.3

CVSS 4.0 · Vendor: VulnCheck

View

Vulnerability Assessment

Weakness

CWE

CWE-95

OWASP Top 10:2025

A05:2025 - Injection

ASVS 5.0

V1 - Encoding and Sanitization Eval input sanitization

MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.

1 public PoC No patch listed yet 1.3% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 27, 2026

Remote code execution in vBulletin 5.x and 6.x allows unauthenticated attackers to execute arbitrary PHP code via a crafted request to the ajax/render endpoint. The vulnerability resides in the vB5_Template_Runtime::runMaths() method, where an insufficient regex filter can be bypassed using phpfuck-style encoding to inject and evaluate arbitrary PHP. Publicly available exploit code exists, and no CISA KEV listing was identified at the time of analysis, but the lack of authentication makes unpatched instances critically exposed.

Affected VersionsENISA

vBulletin 6.0.0 ≤6.2.1

vBulletin patch: 6.2.2

vBulletin 5.0.0 ≤5.7.5

Affected Packages

euvd vbulletin no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 9.3 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

Primary rating from Vendor (VulnCheck) · only source for this CVE.

CVSS VectorVendor: VulnCheck

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

None

User Interaction

None

Vulnerable system: Confidentiality

High

Vulnerable system: Integrity

High

Vulnerable system: Availability

High

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

DescriptionCVE.org

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.

Articles & Coverage 1

News 4 New PHP Vulnerabilities - 3 Critical, 2 With POC Jul 28, 2026

Latest POC

1 public PoC link from nuclei

Threat Intelligence Overview

EPSS Score

1.3%

Top 33% exploitable

Social Media

Sightings

Data Quality

6 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS

Vulnrichment POC (1) CIRCL

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC Yes

EPSS 1.3%

Patch available No

Active threat No

Deciding rule

CRITICAL severity + public POC available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation

Poc

System Exposure· derived

Open

Automatable

Yes

Human Impact· derived

Medium

Technical Impact

Total

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +46

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.