Password Change Bypass in Concrete CMS

Publication date: 2026-05-21

Last updated on: 2026-05-26

Assigner: ConcreteCMS

Description

Concrete CMS below 9.5.0 and below is vulnerable to password change without reauthorization and session-hardening bypass. The user-profile edit controller passes the entire raw POST array to UserInfo::update() without field whitelisting resulting in password change without requiring the current password and also resulting in registered users able to disable the per-user-IP-pinning in the session validator which is meant to detect hijacking. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 5.3 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks 0x4c616e 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-2026-8327

EUVD

EUVD-2026-31362

Affected Vendors & Products

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

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-269	The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
CWE-620	When setting a new password for a user, the product does not require knowledge of the original password, or using another form of authentication.
CWE-915	The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.

Attack-Flow Graph

Executive Summary

This vulnerability affects Concrete CMS versions below 9.5.0. It allows an attacker to change a user's password without needing to provide the current password. This happens because the user-profile edit controller passes the entire raw POST data to the update function without restricting which fields can be changed. Additionally, registered users can disable the per-user-IP-pinning feature in the session validator, which is designed to detect session hijacking.

Impact Analysis

An attacker or a malicious user could change another user's password without authorization, potentially locking the legitimate user out of their account. Furthermore, by disabling the IP-pinning session validation, attackers can bypass session-hardening mechanisms, increasing the risk of session hijacking and unauthorized access.

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