Auth bypass in Contao
CVE-2026-107851
Contao is an Open Source CMS. From version 5.7.0 until 5.7.12, TableAccessVoter::hasAccessToModule() in core-bundle/src/Security/Voter/DataContainer/TableAccessVoter.php caches authorization decisions using only $tokenHash, a hash of the user's security token, and omits the table returned by getDataSource(). If one request first checks a table allowed to the user and then a different denied table, the voter can reuse the allowed result, while DefaultDataContainerVoter can convert an incorrect abstention into a grant. A low-privileged backend user can consequently read, create, update, or delete records in tables outside assigned module permissions, including tables containing member or newsletter-subscriber data. This issue is fixed in version 5.7.12.
Published .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Contao — versions >= 5.7.0, < 5.7.12
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-107851?
- CVE-2026-107851 is a medium-severity vulnerability in Contao, classified under Use of Cache Containing Sensitive Information. CVSS score: 4.3/10. Published 2026-10-09.
- How severe is CVE-2026-107851?
- Medium severity. CVSS v3 base score is 4.3 out of 10.