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Discourse ReactionsFramework / library · Discourse

CVE-2021-41140

MEDIUM · 5.3 CVSS v3.1 Published 2021-10-19
Fix available
A fix is available. Upgrade to 0.2 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click Patch available

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-reactions is a plugin for the Discourse platform that allows user to add their reactions to the post. In affected versions reactions given by user to secure topics and private messages are visible. This issue is patched in version 0.2 of discourse-reaction. Users who are unable to update are advised to disable the Discourse-reactions plugin in admin panel.

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

A detailed technical summary for this CVE is being prepared.

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
Discourse ReactionsFramework / library
Affected:< 0.2

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
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

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

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 0.2 or later
Fixed in 0.2
Vendor patch github.com →
Recommended fix High confidence

Discourse Reactions version 0.2 or later

  1. Back up your Discourse instance and database before making any changes
  2. Navigate to your Discourse server's docker directory (typically /var/discourse)
  3. Edit the app.yml file and update the discourse-reactions plugin line to specify version 0.2 or later (e.g., - git: https://github.com/discourse/discourse-reactions.git; branch: main or a specific version tag)
  4. Run ./launcher rebuild app to rebuild the Discourse container with the updated plugin
  5. After rebuild completes, log in as an admin user
  6. Test that reactions on secure topics and private messages are no longer visible to unauthorized users to verify the fix is working
  7. If unable to upgrade immediately, disable the Discourse-reactions plugin from the Admin > Plugins panel as a temporary mitigation
Caveat Review release notes for any breaking changes before upgrading; test in a staging environment first

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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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-2021-41140 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
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