Contao up to 5.7.6 VirtualFilesystem resolve jobUuid authorization

Summaryinfo

A vulnerability categorized as problematic has been discovered in Contao up to 5.7.6. This affects the function VirtualFilesystem::resolve of the component VirtualFilesystem. The manipulation of the argument jobUuid results in authorization. This vulnerability is cataloged as CVE-2026-55825. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Contao up to 5.7.6. It has been classified as problematic. Affected is the function VirtualFilesystem::resolve of the component VirtualFilesystem. The manipulation of the argument jobUuid with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. This is going to have an impact on confidentiality. CVE summarizes:

Contao is an Open Source CMS. In versions 5.7.0 through 5.7.6, an authenticated backend user who can access one job can request an attachment identifier containing ../ segments and make the job attachment download endpoint read a file from another job directory inside var/job-attachments. The controller authorizes only the jobUuid route parameter. The later attachment lookup joins that authorized job UUID with the attacker-controlled identifier, then passes the combined path to the virtual filesystem. VirtualFilesystem::resolve() canonicalizes the whole path and only rejects paths that escape the filesystem mount, so authorized-job/../victim-job/debug_log.csv becomes victim-job/debug_log.csv. This is a cross-job authorization bypass for known job attachment paths. It is not a practical brute-force against unknown jobs because job directories are UUID v4 values.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-55825 since 06/17/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit.

Upgrading to version 5.7.7 eliminates this vulnerability.

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Productinfo

Name

• Contao

Version

• 5.7.0
• 5.7.1
• 5.7.2
• 5.7.3
• 5.7.4
• 5.7.5
• 5.7.6

Website

• Product: https://github.com/contao/contao/

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