CVE-2026-81913

Concrete CMS versions 9.5.0 through 9.5.2 are vulnerable to Open Redirect via the rcURL parameter. An attacker can craft a single link on the site's own domain that sends a user to an arbitrary external site immediately after authentication, facilitating phishing and credential theft. The same handling is present in the registration flow, giving a second entry point on sites with registration enabled. Concrete CMS versions prior to 9.5.0 do not include the rcURL parameter or this allowlist and are not affected. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.3 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Michal M. 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

24 Sep 2026, 20:13

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 6.1
First Time		Concretecms Concretecms concrete Cms
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 : 2026-09-11 20:19

Updated : 2026-09-24 20:13

NVD link : CVE-2026-81913

Mitre link : CVE-2026-81913

CVE.ORG link : CVE-2026-81913

JSON object : View

Products Affected

concretecms

concrete_cms

CWE

CWE-601

URL Redirection to Untrusted Site ('Open Redirect')

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