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DiscourseApplication

CVE-2026-33291

MEDIUM · 5.4 CVSS v3.1 Published 2026-03-20
Fix available
A fix is available. Upgrade to 2026.1.2 / 2026.2.1 or later.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, moderators can create Zendesk tickets for topics they do not have access to view. This affects all forums that use the Zendesk plugin. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A broken access control vulnerability in Discourse's Zendesk plugin allows moderators to create tickets for topics they lack view permissions for. This results in information disclosure through Zendesk tickets containing content the moderator should not access.

MitigationUpgrade Discourse to version 2026.3.0-latest.1, 2026.2.1, or 2026.1.2 which contains the patched authorization checks for the Zendesk plugin.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
DiscourseApplication
Affected:>= 2026.1.0, < 2026.1.2>= 2026.2.0, < 2026.2.1= 2026.3.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Zendesk plugin is enabled
    Navigate to Admin > Plugins or check the plugins directory to confirm the Zendesk plugin is installed and active
    Affected if The Zendesk plugin is enabled and the Discourse version falls within the affected ranges (2026.1.0 to 2026.1.1, 2026.2.0 to 2026.2.0, or exactly 2026.3.0)
  2. Check installed Discourse version
    Navigate to Admin > Dashboard or check the version file/codebase to determine the exact Discourse version running
    Affected if The installed version is >= 2026.1.0 and < 2026.1.2, OR >= 2026.2.0 and < 2026.2.1, OR equals 2026.3.0
  3. Confirm moderator role exists with restricted topics
    Review the moderator permissions and identify topics or categories that have view restrictions based on group membership
    Affected if Moderators exist who should not have access to certain topics but the Zendesk plugin can be used to create tickets for those topics
  4. Verify Zendesk integration is configured
    Check the Zendesk plugin settings at Admin > Plugins > Zendesk to see if an API connection to Zendesk is configured and active
    Affected if The Zendesk plugin is connected to a Zendesk account, allowing ticket creation from within Discourse

A user is affected if the Zendesk plugin is enabled, the Discourse version is within the vulnerable ranges, and moderators can create Zendesk tickets for topics they lack permission to view, resulting in unauthorized content being exposed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2026.1.2 / 2026.2.1 or later
Fixed in 2026.1.22026.2.1
Interim mitigation

Upgrade Discourse to version 2026.3.0-latest.1, 2026.2.1, or 2026.1.2 which contains the patched authorization checks for the Zendesk plugin.

Recommended fix High confidence

2026.3.0-latest.1 (or 2026.2.1 or 2026.1.2 depending on your release branch)

  1. 1. Identify your current Discourse version by checking the /admin dashboard or running `discourse version`
  2. 2. Determine which stable release branch is appropriate for your deployment (2026.1.x, 2026.2.x, or 2026.3.x)
  3. 3. For Docker-based installations: run `./launcher rebuild app` after updating your configuration to use the target version tag
  4. 4. For source installations: pull the latest code from the Discourse repository and checkout the appropriate version tag (v2026.1.2, v2026.2.1, or v2026.3.0-latest.1)
  5. 5. Verify the upgrade completed successfully and confirm the Zendesk plugin is functioning correctly
  6. 6. Test that moderators can only create Zendesk tickets for topics they have proper access to view

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Discourse Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-33291 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data