Discourse prior 3.5.4/2025.11.2/2025.12.1/2026.1.0 Private Message authorization

Summaryinfo

A vulnerability marked as problematic has been reported in Discourse. This vulnerability affects unknown code of the component Private Message Handler. This manipulation causes authorization. This vulnerability is handled as CVE-2025-68933. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Discourse and classified as problematic. Affected by this vulnerability is an unknown code of the component Private Message Handler. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, non-admin moderators with the `moderators_change_post_ownership` setting enabled can change ownership of posts in private messages and restricted categories they cannot access, then export their data to view the content. This is a broken access control vulnerability affecting sites that grant moderators post ownership transfer permissions. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. The patch adds visibility checks for both the topic and posts before allowing ownership transfer. As a workaround, disable the `moderators_change_post_ownership` site setting to prevent non-admin moderators from using the post ownership transfer feature.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2025-68933 since 12/25/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation needs additional levels of successful authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-206428). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Chat Software

Name

• Discourse

License

• open-source

Website

• Product: https://github.com/discourse/discourse/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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