CVE-2023-34250: Discourse vulnerable to exposure of number of topics recently created in private categories

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-06-13 · updated 2026-06-17
Weakness: CWE-200

Description

Discourse is an open source discussion platform. Prior to version 3.0.4 of the `stable` branch and version 3.1.0.beta5 of the `beta` and `tests-passed` branches, an attacker could use the new topics dismissal endpoint to reveal the number of topics recently created (but not the actual content thereof) in categories they didn't have access to. This issue is patched in version 3.0.4 of the `stable` branch and version 3.1.0.beta5 of the `beta` and `tests-passed` branches. There are no known workarounds.

Affected products

discourse: before 3.0.4; 3.1.0-beta1, 3.1.0-beta2, 3.1.0-beta3, 3.1.0-beta4 — fixed in 3.0.4

How to fix

Upgrade to a fixed version: discourse 3.0.4. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2023-34250 or the next vulnerability affects your stack