Is CVE-2026-107851 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-107851 being exploited in the wild.

How severe is CVE-2026-107851?

Medium severity, with a CVSS score of 4.3, published 9 October 2026.

Which products and versions are affected?

contao/core-bundle (Packagist) >= 5.7.0, < 5.7.12, ECOSYSTEM:introduced=5.7.0,fixed=5.7.12.

Is there a fix for CVE-2026-107851?

Yes. contao/core-bundle (Packagist): upgrade to 5.7.12 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-107851 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-107851?

Check whether you run Contao or contao/core-bundle (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-107851: Contao improper access control in table access voter

Q: Is there a fix for CVE-2026-107851?

Yes. contao/core-bundle (Packagist): upgrade to 5.7.12 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-107851 attacked?

It is attacked over the network, in a web application.

Q: Am I affected by CVE-2026-107851?

Check whether you run Contao or contao/core-bundle (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-107851 · Severity: medium · CVSS 4.3 · Published 2026-10-09

Contao is a content management system used to manage website content and backend user permissions. A caching bug in the backend's access control allows a low-privileged user to bypass table-level restrictions and gain unauthorized access to sensitive data like member records and newsletter subscriber lists. An attacker with any backend account can read, modify, or delete data they should not be permitted to access.

Technologies: Contao, contao/core-bundle (Packagist). Vendors: Contao, Packagist.

Quick answers

Is CVE-2026-107851 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-107851 being exploited in the wild.
How severe is CVE-2026-107851?: Medium severity, with a CVSS score of 4.3, published 9 October 2026.
Which products and versions are affected?: contao/core-bundle (Packagist) >= 5.7.0, < 5.7.12, ECOSYSTEM:introduced=5.7.0,fixed=5.7.12.
Is there a fix for CVE-2026-107851?: Yes. contao/core-bundle (Packagist): upgrade to 5.7.12 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-107851 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-107851?: Check whether you run Contao or contao/core-bundle (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

contao/core-bundle (Packagist): upgrade to 5.7.12 or later
```
composer require contao/core-bundle:^5.7.12
```

Technical details

A security voter in Contao's Data Container caches access decisions using only the user's security token as the key, omitting the table identifier. This causes the cached result from checking one table to be reused for subsequent table checks within the same request, bypassing per-table access control. Most tables lack a secondary check, allowing a permissive fallback voter to grant access when the defective cache returns no opinion.

Affected products

Contao Contao

Identifiers

CVE-2026-107851
GHSA-5974-gfqc-wrcm

Timeline

2026-10-09: disclosed

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