opf openproject up to 17.3.2/17.4.0 Attachments Stimulus.js renderStreamMessage cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, was found in opf openproject up to 17.3.2/17.4.0. The impacted element is the function renderStreamMessage of the file Stimulus.js of the component Attachments Handler. Such manipulation leads to cross site scripting. This vulnerability is listed as CVE-2026-52781. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in opf openproject up to 17.3.2/17.4.0. Affected by this issue is the function renderStreamMessage of the file Stimulus.js of the component Attachments Handler. 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. CVE summarizes:

OpenProject is open-source, web-based project management software. Prior to 17.3.3 and 17.4.1, the HTML sanitizer grants elements unrestricted data-* attributes via :data wildcard. An attacker injects data-controller="poll-for-changes" into a work package description, causing Stimulus.js to mount a controller that fetches an attacker-uploaded attachment and passes it to renderStreamMessage(). This executes arbitrary Turbo Stream actions — including redirect_to — in every victim's authenticated browser session, redirecting them to an attacker-controlled server. This vulnerability is fixed in 17.3.3 and 17.4.1.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-52781 since 06/08/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 17.3.3 or 17.4.1 eliminates this vulnerability.

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Productinfo

Type

• Project Management Software

Vendor

• opf

Name

• openproject

Version

• 17.0
• 17.1
• 17.2
• 17.3
• 17.3.0
• 17.3.1
• 17.3.2
• 17.4.0

Website

• Product: https://github.com/opf/openproject/

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