CVE-2023-23935 (published 2023-03-16T20:21:13.539Z)
Discourse is an open-source messaging platform. In versions 3.0.1 and prior on the `stable` branch and versions 3.1.0.beta2 and prior on the `beta` and `tests-passed` branches, the count of personal messages displayed for a tag is a count of all personal messages regardless of whether the personal message is visible to a given user. As a result, any users can technically poll a sensitive tag to determine if a new personal message is created even if the user does not have access to the personal message.

In the patched versions, the count of personal messages tagged with a given tag is hidden by default. To revert to the old behaviour of displaying the count of personal messages for a given tag, an admin may enable the `display_personal_messages_tag_counts` site setting.
Affected products: Vendor: discourse
Product: discourse
Versions: stable <= 3.0.1, beta <= 3.1.0.beta2, tests-passed <= 3.1.0.beta2