CVE-2026-45085 Details
Description
Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.4, 2026.3.0-latest to before 2026.3.1, and 2026.4.0-latest to before 2026.4.1, four authorization/disclosure issues in the chat plugin (one also involving discourse-calendar): read-only category users could create chat threads, self-deleted chat messages could be restored by their author after channel access was revoked, moderators reviewing a flagged chat message were shown the channel's current last_message (often unrelated DM content), and calendar event payloads exposed the attached chat channel and its last message to viewers without chat access (including anonymous users). This affects sites with the chat plugin enabled; the calendar issue additionally requires discourse-calendar. This issue has been patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026.5.0-latest.1.
A vulnerability in the Discourse chat plugin has been identified, affecting versions 2026.1.0-latest prior to 2026.1.4, 2026.3.0-latest prior to 2026.3.1, and 2026.4.0-latest prior to 2026.4.1. This vulnerability introduces four authorization and information disclosure issues. In read-only categories, users could create chat threads. Additionally, self-deleted messages could be restored after channel access was revoked. Moderators reviewing flagged messages were inadvertently shown unrelated direct message content. Lastly, calendar event payloads exposed chat channel details and last messages to viewers without chat access, including anonymous users. The vulnerability requires the chat plugin to be enabled, and the calendar issue additionally requires the discourse-calendar plugin.
Users can upgrade to Discourse versions 2026.1.4, 2026.3.1, 2026.4.1, or 2026.5.0-latest.1. Disabling the chat plugin removes all exposure, while detaching chat channels from public calendar events mitigates the calendar-related information leak.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 15, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/discourse/discourse/security/advisories/GHSA-rw8j-p2gv-q33w | [email protected] | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-200 | Exposure of Sensitive Information to an Unauthorized Actor | [email protected] |
| CWE-862 | Missing Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| discourse discourse | < 2026.1.0 >= 2026.1.0, < 2026.1.4 >= 2026.3.0, < 2026.3.1 >= 2026.4.0, < 2026.4.1 2026.5.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | Initial Analysis | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 12, 2026 | New CVE Received | [email protected] |