CVE-2026-55825
LowCVSS 3.1Exploitation Probability (EPSS)
Low risk11th percentile - higher than 11% of all known CVEs
Summary
Contao CMS versions 5.7.0 through 5.7.6 contain a cross-job authorization bypass vulnerability. An authenticated backend user can read attachments from other jobs by manipulating the attachment identifier with '../' sequences.
Risk Assessment
An attacker can access sensitive attachment files from other jobs, potentially leading to data leakage.
Recommendation
Update Contao to version 5.7.7 or later, which includes the fix.
Original NVD description (English source)
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.