CVE-2026-81925

Concrete CMS before 9.5.3 improperly neutralized a user-supplied custom date format when rendering conversation messages, resulting in reflected cross-site scripting. An attacker could execute arbitrary JavaScript in the browser of a user who was tricked into submitting a crafted POST request to the conversation view endpoint. Exploitation was aided by the absence of a CSRF token on the endpoint, which allowed the payload to be delivered through an auto-submitting cross-origin POST without authentication. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

CVSS v3 6.1 MEDIUM

6.1^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 2.7

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes	Broken Link

Configurations

Configuration 1 (hide)

cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*

History

21 Sep 2026, 17:53

Type	Values Removed	Values Added
First Time		Concretecms Concretecms concrete Cms
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 6.1
CPE		cpe:2.3:a:concretecms:concrete_cms::::::::
References	~~() https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes -~~	() https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes - Broken Link

Information

Published : 2026-09-15 20:18

Updated : 2026-09-21 17:53

NVD link : CVE-2026-81925

Mitre link : CVE-2026-81925

CVE.ORG link : CVE-2026-81925

JSON object : View

Products Affected

concretecms

concrete_cms

CWE

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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