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CVE-2026-8428

CVE-2026-8428 · CSRF token is not validated in the core CMS update controller for Concrete CMS 9.5.0 and below

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token->output('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this->token->validate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.

CVSS 7.5 · High · EPSS 0.1% · Fix available

Published
Updated

Stack: php

Affected products and versions

  • concrete cms

    Versions
    • ≥ 5.0, ≤ 9.5.0: Affected (git)

    No fix published

  • concrete5/concrete5 Packagist

    Versions
    • 8.0
    • 8.0.1
    • 8.0.2
    • 8.0.3
    • 8.1.0
    • 8.2.0
    • 8.2.0RC2
    • 8.2.1
    • 8.3.0
    • 8.3.1
    • 8.3.2
    • 8.4.0
    • 8.4.0RC3
    • 8.4.0RC4
    • 8.4.1
    • 8.4.2
    • 8.4.3
    • 8.4.4
    • 8.4.5
    • 8.5.0
    • 8.5.0RC1
    • 8.5.0RC2
    • 8.5.1
    • 8.5.10
    • 8.5.11
    • 8.5.12
    • 8.5.13
    • 8.5.14
    • 8.5.15
    • 8.5.16
    • 8.5.17
    • 8.5.18
    • 8.5.19
    • 8.5.2
    • 8.5.20
    • 8.5.21
    • 8.5.3
    • 8.5.4
    • 8.5.5
    • 8.5.6
    • 8.5.6RC1
    • 8.5.7
    • 8.5.8
    • 8.5.9
    • 9.0.0
    • 9.0.0RC1
    • 9.0.0RC3
    • 9.0.0RC4
    • 9.0.1
    • 9.0.2
    • 9.1.0
    • 9.1.1
    • 9.1.2
    • 9.1.3
    • 9.2.0
    • 9.2.0RC2
    • 9.2.1
    • 9.2.2
    • 9.2.3
    • 9.2.4
    • 9.2.5
    • 9.2.6
    • 9.2.7
    • 9.2.8
    • 9.2.9
    • 9.3.0
    • 9.3.1
    • 9.3.2
    • 9.3.3
    • 9.3.4
    • 9.3.5
    • 9.3.6
    • 9.3.7
    • 9.3.8
    • 9.3.9
    • 9.4.0
    • 9.4.0RC1
    • 9.4.0RC2
    • 9.4.1
    • 9.4.2
    • 9.4.3
    • 9.4.4
    • 9.4.5
    • 9.4.6
    • 9.4.7
    • 9.4.8
    • 9.5.0
    • 9.5.0RC1
    • 9.5.0RC2
    Affected ranges
    • ECOSYSTEM: < 9.5.1

    Update to 9.5.1

Original sources

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