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CVE-2026-33410— Discourse hardens chat DM channel creation and expansion

Quick assessment

Affected
discourse discourse
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Discourse是Discourse开源的一套开源的社区讨论平台。该平台包括社区、电子邮件和聊天室等功能。 Discourse 2026.3.0-latest.1之前版本、2026.2.1之前版本和2026.1.2之前版本存在安全漏洞，该漏洞源于聊天私信API中存在两处授权问题，可能导致经过身份验证的聊天用户泄露私密群组成员身份，或聊天功能被禁用的用户通过API查询其他用户之间的私信频道内容。

CVSS 5.4 · Medium EPSS 0.25% · P15
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I. Basic Information for CVE-2026-33410

Vulnerability Information
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Vulnerability Title
Discourse hardens chat DM channel creation and expansion
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不正确
Source: CVE Program / CVE List V5
Vulnerability Title
Discourse 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Discourse是Discourse开源的一套开源的社区讨论平台。该平台包括社区、电子邮件和聊天室等功能。 Discourse 2026.3.0-latest.1之前版本、2026.2.1之前版本和2026.1.2之前版本存在安全漏洞，该漏洞源于聊天私信API中存在两处授权问题，可能导致经过身份验证的聊天用户泄露私密群组成员身份，或聊天功能被禁用的用户通过API查询其他用户之间的私信频道内容。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
discourse discourse >= 2026.1.0-latest, < 2026.1.2 -

II. Public POCs for CVE-2026-33410

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III. Intelligence Information for CVE-2026-33410

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Vendor Advisories for CVE-2026-33410 (1)

Same Patch Batch · discourse · 2026-03-19 · 17 CVEs total

CVE-2026-33355 6.5 MEDIUM Discourse filters whisper posts from private-posts feed
CVE-2026-27454 5.3 MEDIUM Discourse has check revision visibility on posts endpoint
CVE-2026-33395 4.4 MEDIUM Discourse has stored click‑based XSS via Graphviz SVG javascript: links
CVE-2026-32099 4.3 MEDIUM Discourse prevents hidden profile data leak via user onebox
CVE-2026-33393 4.3 MEDIUM Discourse fixes loose hostname matching in spam host allowlist
CVE-2026-27166 4.1 MEDIUM Discourse vulnerable to HTML injection via prohibited iframe URLs
CVE-2026-33394 2.7 LOW Discourse leaks PM post edits to moderators
CVE-2026-33408 2.2 LOW Discourse has Improper Authorization in "Post Edits" Report For Moderators
CVE-2026-27491 Discourse has a bypass of official warnings messages by non-staff users
CVE-2026-27570 Discourse Vulnerable to Stored XSS via Shared AI Conversation Onebox
CVE-2026-27740 Discourse has Stored XSS in AI Triage Automation
CVE-2026-27934 Discourse leaks private topic title and post excerpt via user action API endpoint
CVE-2026-27935 Discourse leaks private topic metadata to non-authorized users
CVE-2026-27936 Discourse discloses restricted post-action counts to non-privileged users
CVE-2026-28282 Discourse vulnerable to group membership addition permission bypass via discourse-policy p
CVE-2026-29072 Discourse missing permission check for policy creation in discourse-policy

IV. Related Vulnerabilities

Same product: discourse
Same vendor: discourse
Same weakness: CWE-863

V. Comments for CVE-2026-33410

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