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CVE-2026-107850

CVE-2026-107850 · Contao: Improper access control in the preview links module

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

Contao is an Open Source CMS. From version 5.7.1 until 5.7.12, core-bundle/config/services.yaml registers the preview access voter as Contao\CoreBundle\Security\Voter\DataContainer\PreviewAccessVoter although the shipped class is PreviewVoter. Symfony therefore omits voter autoconfiguration and removes the private service, so PreviewVoter::hasAccess() never enforces ownership. A non-admin backend user with the preview_link module can list every tl_preview_link record, obtain signed share URLs created by other users, and use them to view unpublished pages with showUnpublished despite lacking page permission. The advisory does not establish editing or deletion of foreign links. This issue is fixed in version 5.7.12.

CVSS 4.3 · Medium · EPSS 0.2% · Fix available

Published
Updated

Stack: php

Affected products and versions

  • contao

    Versions
    • >= 5.7.1, < 5.7.12: Affected

    No fix published

  • contao/core-bundle Packagist

    Versions
    • 5.7.1
    • 5.7.10
    • 5.7.11
    • 5.7.2
    • 5.7.3
    • 5.7.4
    • 5.7.5
    • 5.7.6
    • 5.7.7
    • 5.7.8
    • 5.7.9
    Affected ranges
    • ECOSYSTEM: ≥ 5.7.1, < 5.7.12

    Update to 5.7.12

Original sources

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