What’s Vulnerable › Vulnerabilities

CVE-2021-32788: Post creator of a whisper post can be revealed to non-staff users in Discourse

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-27 · updated 2026-06-17
• Weakness: CWE-668

Description

Discourse is an open source discussion platform. In versions prior to 2.7.7 there are two bugs which led to the post creator of a whisper post being revealed to non-staff users. 1: Staff users that creates a whisper post in a personal message is revealed to non-staff participants of the personal message even though the whisper post cannot be seen by them. 2: When a whisper post is before the last post in a post stream, deleting the last post will result in the creator of the whisper post to be revealed to non-staff users as the last poster of the topic.

Affected products

• discourse: before 2.7.7 — fixed in 2.7.7

How to fix

Upgrade to a fixed version: discourse 2.7.7. Check the vendor advisory for mitigations.

References

• https://github.com/discourse/discourse/commit/680024f9071b7696e5a444a58791016c6dc1f1e5
• https://github.com/discourse/discourse/commit/dbdf61196d9e964e8823793d2e7f856595fea4d9
• https://github.com/discourse/discourse/security/advisories/GHSA-v6xg-q577-vc92
• https://github.com/discourse/discourse/commit/680024f9071b7696e5a444a58791016c6dc1f1e5
• https://github.com/discourse/discourse/commit/dbdf61196d9e964e8823793d2e7f856595fea4d9
• https://github.com/discourse/discourse/security/advisories/GHSA-v6xg-q577-vc92

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