CVE-2022-39378: Displaying user badges can leak topic titles to users that have no access to the topic

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-11-02 · updated 2026-06-17
Weakness: CWE-200

Description

Discourse is a platform for community discussion. Under certain conditions, a user badge may have been awarded based on a user's activity in a topic with restricted access. Before this vulnerability was disclosed, the topic title of the topic associated with the user badge may be viewed by any user. If there are sensitive information in the topic title, it will therefore have been exposed. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. There are currently no known workarounds available.

Affected products

discourse: before 2.8.9; 2.9.0-beta1, 2.9.0-beta2, 2.9.0-beta3, 2.9.0-beta4, 2.9.0-beta5, 2.9.0-beta6 (+3) — fixed in 2.8.9

How to fix

Upgrade to a fixed version: discourse 2.8.9. Check the vendor advisory for mitigations.

References

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