CVE-2026-33410 Details
Description
Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have two authorization issues in the chat direct message API. First, when creating a direct message channel or adding users to an existing one, the `target_groups` parameter was passed directly to the user resolution query without checking group or member visibility for the acting user. An authenticated chat user could craft an API request with a known private/hidden group name and receive a channel containing that group's members, leaking their identities. Second, `can_chat?` only checked group membership, not the `chat_enabled` user preference. A chat-disabled user could create or query DM channels between other users via the direct messages API, potentially exposing private `last_message` content from the serialized channel response. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.
Two authorization vulnerabilities have been identified in the Discourse chat direct message API, affecting versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2. The first issue allows an authenticated chat user to bypass group visibility controls. When creating or modifying direct message channels, the 'target_groups' parameter was sent directly to the user resolution query without verifying group or member visibility for the user. This flaw enabled the extraction of members' identities from known private or hidden groups. The second issue arises from the 'can_chat?' check, which only considered group membership and ignored the 'chat_enabled' user preference. As a result, a chat-disabled user could manipulate the direct messages API to create or access DM channels between other users, potentially revealing private 'last_message' content from the channel's serialized response.
Users are advised to upgrade to Discourse versions 2026.3.0-latest.1, 2026.2.1, or 2026.1.2.
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 Mar 20, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/discourse/discourse/security/advisories/GHSA-2m5j-6v2r-cq2h | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| discourse discourse | >= 2026.1.0, < 2026.1.2 >= 2026.2.0, < 2026.2.1 2026.3.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Mar 24, 2026 | Initial Analysis | [email protected] |
| Mar 19, 2026 | New CVE Received | [email protected] |