CVE-2021-41082: Private message title and participating users leaked in discourse

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-20 · updated 2026-06-17
Weakness: CWE-200

Description

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.

Affected products

discourse: before 2021-09-14 — fixed in 2021-09-14

How to fix

Upgrade to a fixed version: discourse 2021-09-14. Check the vendor advisory for mitigations.

References

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