CVE-2022-21684: User can bypass approval when invited to Discourse

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-01-13 · updated 2026-06-17
Weakness: CWE-287

Description

Discourse is an open source discussion platform. Versions prior to 2.7.13 in `stable`, 2.8.0.beta11 in `beta`, and 2.8.0.beta11 in `tests-passed` allow some users to log in to a community before they should be able to do so. A user invited via email to a forum with `must_approve_users` enabled is going to be automatically logged in, bypassing the check that does not allow unapproved users to sign in. They will be able to do everything an approved user can do. If they logout, they cannot log back in. This issue is patched in the `stable` version 2.7.13, `beta` version 2.8.0.beta11, and `tests-passed` version 2.8.0.beta11. One may disable invites as a workaround. Administrators can increase `min_trust_level_to_allow_invite` to reduce the attack surface to more trusted users.

Affected products

discourse: before 2.7.13; 2.8.0-beta1, 2.8.0-beta10, 2.8.0-beta2, 2.8.0-beta3, 2.8.0-beta4, 2.8.0-beta5 (+4) — fixed in 2.7.13

How to fix

Upgrade to a fixed version: discourse 2.7.13. Check the vendor advisory for mitigations.

References

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