IDOR Vulnerability in Concrete CMS by Concrete5
CVE-2026-8347

2.3LOW

Key Information:

Vendor

Concrete Cms

Status
Concrete Cms
Vendor
CVE Published:
22 May 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-8347?

A vulnerability in Concrete CMS versions 9.5.0 and earlier allows an attacker to exploit IDOR (Insecure Direct Object Reference) and incorrect authorization levels in the Express association Reorder dialog. This could enable a malicious user to manipulate state across entities with view-only permissions for specific entries. For a site to be vulnerable, it must utilize the express feature and depend on express entity ordering. The submission of this vulnerability was made by Winston Crooker.

Affected Version(s)

Concrete CMS 5.0 <= 9.5.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-8347
Created by aj2108

References

https://documentation.concretecms.org/9-x/developers/intr...
release-notes

CVSS V4

Score:
2.3
Severity:
LOW
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Winston Crooker
.