CVE-2026-7882

Analyzed Analyzed - Analysis Complete

Concrete CMS Unauthorized File Deletion via Inverted CSRF Check

Publication date: 2026-05-21

Last updated on: 2026-05-26

Assigner: ConcreteCMS

Description

Concrete CMS 9.5.0 and below is vulnerable to unauthorized file deletion due to an Inverted CSRF token check in the DeleteFile controller. The code throws an error when the token IS valid and proceeds with file deletion when the token is invalid or missing. This effectively disables CSRF protection for the file deletion endpoint, allowing cross-site request forgery attacks against users who have permission to edit conversation messages. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.3 with a vector of CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Tristan Mandani for reporting.

CVSS Scores

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Meta Information

Published

2026-05-21

Last Modified

2026-05-26

Generated

2026-07-02

AI Q&A

2026-05-22

EPSS Evaluated

2026-06-30

NVD

CVE-2026-7882

EUVD

EUVD-2026-31361

Affected Vendors & Products

Vendor	Product	Version / Range
concretecms	concrete_cms	to 9.5.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-352	The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.

Attack-Flow Graph

Executive Summary

Concrete CMS version 9.5.0 and below has a vulnerability in its DeleteFile controller caused by an inverted CSRF token check. Instead of preventing unauthorized actions when the CSRF token is invalid or missing, the code erroneously throws an error when the token is valid and proceeds with file deletion when the token is invalid or missing. This flaw disables CSRF protection for the file deletion endpoint.

As a result, attackers can perform cross-site request forgery (CSRF) attacks to delete files without proper authorization, targeting users who have permission to edit conversation messages.

Impact Analysis

This vulnerability allows attackers to delete files without proper authorization by exploiting the disabled CSRF protection on the file deletion endpoint.

If you are a user with permission to edit conversation messages, an attacker could trick you into unknowingly deleting files, potentially leading to data loss or disruption of service.

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