CVE-2026-81904

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    CVE-2026-81904

    Published: 8 Sept 2026Last Modified: 12 Sept 2026

    Summary: Concrete CMS before 9.5.3 is vulnerable to Missing Authorization in Stack/Container Sub-Block Asset Registration

    Details: Concrete CMS below 9.5.3 registered view assets for every sub-block of a Stack, Container, or layout area without checking whether the requesting user could view that sub-block. An unauthenticated visitor could recover configuration values emitted by a restricted sub-block's asset registration — such as a site's configured Google Maps API key — from any public page embedding an affected Stack, Container, or layout area, despite the block-level permission restriction. Any sub-block type whose asset or header hooks output configuration values is affected.  The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.

    References: https://documentation.concretecms.org/9-x/developers/introduction/version-history/953-release-notes, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81904.json, https://nvd.nist.gov/vuln/detail/CVE-2026-81904, https://github.com/concretecms/concretecms

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    9.5.2
    9.5.1
    9.5.0
    9.5.0RC2
    9.5.0RC1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2026-81904 | CVE-DB