Private-message disclosure and modification via unscoped AI reviewables
Published Sep 24, 2026 · Updated Sep 24, 2026
Improper access control in Discourse before 2026.7.0 allows remote authenticated users with moderator access to read or alter private messages. Reviewable visibility filtering admits Discourse AI items without checking whether the moderator can access the underlying private-message topic. A site must use Discourse AI, and exploitation requires a pre-existing private-message reviewable; exposed actions can close the topic or delete a post.
Summary
What happened
Improper access control in Discourse before 2026.7.0 allows remote authenticated users with moderator access to read or alter private messages. Reviewable visibility filtering admits Discourse AI items without checking whether the moderator can access the underlying private-message topic. A site must use Discourse AI, and exploitation requires a pre-existing private-message reviewable; exposed actions can close the topic or delete a post.
The record
- CVE
- CVE-2026-84302
- Published
- Sep 24, 2026
- Updated
- Sep 24, 2026
- Vendor
- Discourse
- Product
- Discourse
- Classifications
- T1213
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 24, 2026CVE publishedPublication date reported by the CVE source.
- Sep 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 2026.1.0-latest, < 2026.1.6
- Affected versionversion=>= 2026.5.0-latest, < 2026.5.2
- Affected versionversion=>= 2026.6.0-latest, < 2026.6.1
- Affected versionversion=< 2026.7.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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