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CVE-2026-26207

DIscourse's discourse-policy plugin lacks post access check

5.4 MediumFix available

Discourse 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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
None

Exploit likelihood

0.17%Up 0.1 points since Feb 27, 2026
90%50%10%1%

What each source reports

CVE List Score used5.4

DIscourse's discourse-policy plugin lacks post access check

Discourse 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.

Record
CVE-2026-26207
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Weakness
CWE-862
Updated
2026-11-02
EUVDEUVD-2026-88575.4

Discourse 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.

Record
EUVD-2026-8857
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Updated
2026-11-02
NVD5.4

Discourse 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.

Record
CVE-2026-26207
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Weakness
CWE-862
Updated
2026-11-02
OSV5.4

DIscourse's discourse-policy plugin lacks post access check

Discourse 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.

Record
CVE-2026-26207
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Weakness
CWE-862
Updated
2026-11-02
OSVBIT-discourse-2026-26207No score

DIscourse's discourse-policy plugin lacks post access check

Discourse 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.

Record
BIT-discourse-2026-26207
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
discourse
Bitnami
before 2025.12.2, 2026.1.0 up to 2026.1.1
2025.12.22026.1.1

History

History
RecordedChangedSources
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-26207 is a medium vulnerability (CVSS 5.4) in Discourse, published February 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.17%, the 6th percentile. Fixed in discourse 2025.12.2.

References

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