CVE-2026-55804: Drupal Core Insecure Deserialization Vulnerability

drupal/core Updated 17 Jun 2026

Summary

08/06/2026

Disclosed on

CVE-2026-55804

CVE

Yes i

Fix available

Unrated

Severity

Not published

CVSS Score

CVE-2026-55804: Drupal core contains a chain of methods that could be exploitable when an insecure deserialization vulnerability exists on the site. Affects drupal/core across 6 version ranges.

< 10.5.12 >= 10.6.0, < 10.6.11 >= 11.0.0, < 11.1.0 >= 11.1.0, < 11.2.0 >= 11.2.0, < 11.2.14 >= 11.3.0, < 11.3.12

Fixed in 6 releases; the minimum fixed version depends on the release line you run. How to fix ↓

Also tracked for

drupal · Bitnami

The same CVE-2026-55804 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.

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Background

Drupal is a widely-used open-source content management system (CMS) that allows users to create and manage websites easily. It is known for its flexibility, scalability, and extensive community support. However, like many software systems, Drupal can be vulnerable to security issues. The vulnerability identified as CVE-2026-55804 relates to a chain of methods within Drupal core that could be exploited if an insecure deserialization vulnerability exists on the site.

Vulnerability Detail

The vulnerability in Drupal core is a potential exploit stemming from a 'gadget chain' that could lead to remote code execution or SQL injection if the application deserializes untrusted data due to another vulnerability. While this issue itself is not directly exploitable, it poses a risk if an attacker can pass unsafe input to the unserialize() function, which is a common method for converting serialized data back into PHP variables.

How To Fix

Fixed versions by release line

The minimum fixed version depends on the release line you run.

< 10.5.12 10.5.12
```
composer require drupal/core:10.5.12
```
>= 10.6.0, < 10.6.11 10.6.11
```
composer require drupal/core:10.6.11
```
>= 11.0.0, < 11.1.0 11.1.0
```
composer require drupal/core:11.1.0
```
>= 11.1.0, < 11.2.0 11.2.0
```
composer require drupal/core:11.2.0
```
>= 11.2.0, < 11.2.14 11.2.14
```
composer require drupal/core:11.2.14
```
>= 11.3.0, < 11.3.12 11.3.12
```
composer require drupal/core:11.3.12
```

Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →

Workaround

Currently, there are no specific workarounds mentioned for this vulnerability. The best course of action is to ensure that your Drupal installation is updated to the latest patched version.

Conclusion

In summary, CVE-2026-55804 is a vulnerability in Drupal core related to insecure deserialization that could lead to serious security issues if exploited. It is essential to update to the latest patched versions to protect your application from potential attacks.

See every vulnerability recorded for drupal/core →