CVE-2026-33410: medium-severity vulnerability in discourse
Discourse hardens chat DM channel creation and expansion
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.4epss 0.2%
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Affected products
discourse · discourseRelated CVEs — discourse
In the same product, most dangerous first.
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