rails actionpack up to 8.1/8.1.2.1 consider_all_requests_local cross site scripting

Summaryinfo

A vulnerability has been found in rails actionpack up to 8.1/8.1.2.1 and classified as problematic. Affected by this vulnerability is the function consider_all_requests_local. The manipulation leads to cross site scripting. This vulnerability is traded as CVE-2026-33167. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in rails actionpack up to 8.1/8.1.2.1. This issue affects the function consider_all_requests_local. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

Action Pack is a Rubygem for building web applications on the Rails framework. In versions on the 8.1 branch prior to 8.1.2.1, the debug exceptions page does not properly escape exception messages. A carefully crafted exception message could inject arbitrary HTML and JavaScript into the page, leading to XSS. This affects applications with detailed exception pages enabled (`config.consider_all_requests_local = true`), which is the default in development. Version 8.1.2.1 contains a patch.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-33167 since 03/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 304109 (Linux Distros Unpatched Vulnerability : CVE-2026-33167), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 8.1.2.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 6752711c8c31d79ba50d13af6a6698a3b85415e0 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (304109). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• rails

Name

• actionpack

Version

• 8.0
• 8.1
• 8.1.2.0
• 8.1.2.1

License

• open-source

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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