Discourse is an open-source community platform. A data leak vulnerability affects sites deployed between commits 10df7fdee060d44accdee7679d66d778d1136510 and 82d84af6b0efbd9fa2aeec3e91ce7be1a768511b. On login-required sites, the leak meant that some content on the site's homepage could be visible to unauthenticated users. Only login-required sites that got deployed during this timeframe are affected, roughly between April 30 2025 noon EDT and May 2 2025, noon EDT. Sites on the stable branch are unaffected. Private content on an instance's homepage could be visible to unauthenticated users on login-required sites. Versions of 3.5.0.beta4 after commit 82d84af6b0efbd9fa2aeec3e91ce7be1a768511b are not vulnerable to the issue. No workarounds are available. Sites must upgrade to a non-vulnerable version of Discourse.
Discourse is a platform for community discussion. In affected versions any private message that includes a group had its title and participating user exposed to users that do not have access to the private messages. However, access control for the private messages was not compromised as users were not able to view the posts in the leaked private message despite seeing it in their inbox. The problematic commit was reverted around 32 minutes after it was made. Users are encouraged to upgrade to the latest commit if they are running Discourse against the `tests-passed` branch.