CVE-2026-26207
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 · uneditedDiscourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, `discourse-policy` plugin allows any authenticated user to interact with policies on posts they do not have permission to view. The `PolicyController` loads posts by ID without verifying the current user's access, enabling policy group members to accept/unaccept policies on posts in private categories or PMs they cannot see and any authenticated user to enumerate which post IDs have policies attached via differentiated error responses (information disclosure). The issue is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0 by adding a `guardian.can_see?(@post)` check in the `set_post` before_action, ensuring post visibility is verified before any policy action is processed. As a workaround, disabling the discourse-policy plugin (`policy_enabled = false`) eliminates the vulnerability. There is no other workaround without upgrading.
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 confidenceThe discourse-policy plugin in Discourse has an IDOR vulnerability where the PolicyController loads posts by ID without verifying user access permissions. Any authenticated user can interact with (accept/unaccept) policies on posts they cannot see (private categories or PMs), and can enumerate which post IDs have policies via differentiated error responses, causing information disclosure.
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< 2025.12.0>= 2026.1.0, < 2026.1.1= 2026.2.0CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check Discourse versionNavigate to the Discourse Admin panel, go to /admin, and locate the version number displayed on the dashboard or in the 'About' section. Alternatively, check the version file in your Discourse installation directory.Affected if The installed version is < 2025.12.0, OR >= 2026.1.0 and < 2026.1.1, OR exactly 2026.2.0
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Verify discourse-policy plugin is enabledIn the Discourse Admin panel, navigate to /admin/plugins and review the list of installed and enabled plugins. Confirm that 'discourse-policy' appears in the enabled plugins list.Affected if The discourse-policy plugin is currently enabled in the installation
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Confirm presence of private categories or restricted contentIn the Discourse Admin panel, go to /categories and review which categories have restricted access permissions (visible only to certain groups). Additionally, check if private messages with policies are in use by reviewing post data or policy plugin usage.Affected if There exist private categories with restricted group access, or private message posts that have policy documents attached
You are affected if your Discourse version falls within the vulnerable ranges AND the discourse-policy plugin is enabled AND your forum contains private categories or private messages that use the policy plugin.
Generated from the published advisory. Verify against your own configuration.
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 · scoped2025.12.02026.1.1
Upgrade Discourse to versions 2025.12.2, 2026.1.1, or 2026.2.0 to receive the patched discourse-policy plugin, or disable the plugin entirely as a workaround if upgrading is not immediately feasible.
2025.12.2, 2026.1.1, or 2026.2.0 (depending on your current version branch)
- 1. Identify your current Discourse version by checking the /admin dashboard or running `git log -1` in your Discourse installation directory
- 2. Determine which upgrade path applies based on your current version: if < 2025.12.0, upgrade to 2025.12.2; if >= 2026.1.0 and < 2026.1.1, upgrade to 2026.1.1; if = 2026.2.0, ensure you have the patched 2026.2.0 release
- 3. Back up your Discourse database and files before upgrading
- 4. Run the standard Discourse upgrade process: `./launcher stop app`, then `./launcher rebuild app` or pull latest Docker image
- 5. Verify the upgrade completed successfully and Discourse is operational
- 6. Confirm the vulnerability is patched by checking that the PolicyController now includes the `guardian.can_see?(@post)` authorization check
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-26207 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-26207 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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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