CVE-2026-107851 contao CVE debrief

Who should care

Defenders and administrators of Contao installations should assess exposure and prioritize patching to prevent unauthorized data access. They should review module permissions for low-privileged backend users and monitor for unauthorized access to sensitive tables. Security teams should verify and apply the patch to Contao version 5.7.12 and review compensating controls for exposed systems.

Why it matters

Defenders should care about CVE-2026-107851 as it allows low-privileged backend users to access sensitive data outside their module permissions in Contao. The issue requires verification of exposure and prompt patching to prevent unauthorized data access.

• Potential unauthorized data access
• Elevation of privileges for low-privileged users
• Data tampering or deletion possible

Technical summary

The TableAccessVoter::hasAccessToModule() function in Contao caches authorization decisions using only $tokenHash, omitting the table returned by getDataSource(). This allows a low-privileged backend user to read, create, update, or delete records in tables outside assigned module permissions. The issue requires verification of exposure and prompt patching to prevent unauthorized data access. The vulnerability is fixed in Contao version 5.7.12, and defenders should prioritize applying the patch to prevent exploitation.

Defensive priority

Defenders should prioritize verifying and applying the patch to prevent unauthorized data access.

Recommended defensive actions

• Verify and apply the patch to Contao version 5.7.12
• Review and update module permissions for low-privileged backend users
• Monitor for unauthorized access to sensitive tables
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the vulnerability and its fix. The issue is confirmed in Contao versions 5.7.0 through 5.7.11. Defenders should verify exposure and apply the patch to prevent unauthorized data access. Evidence is based on the CVE Program record and source item details, with limitations on affected scope and severity.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.