CVE-2026-26973
Feb. 27, 2026, 2:06 p.m.
4.3
Medium
Description
Discourse is an open source discussion platform. Versions prior to 2025.12.2, 2026.1.1, and 2026.2.0 have an IDOR (Insecure Direct Object Reference) in `ReviewableNotesController`. When `enable_category_group_moderation` is enabled, a user belonging to a category moderation group can create or delete their own notes on **any** reviewable in the system, including reviewables in categories they do not moderate. The controller used an unscoped `Reviewable.find` and the `ensure_can_see` guard only checked whether the user could access the review queue in general, not whether they could access the specific reviewable. Only instances with `enable_category_group_moderation` enabled are affected. Staff users (admins/moderators) are not impacted as they already have access to all reviewables. The issue is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0 by scoping the reviewable lookup through `Reviewable.viewable_by(current_user)`. As a workaround, disable the `enable_category_group_moderation` site setting. This removes the attack surface as only staff users will have access to the review queue.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Discourse |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-863
Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | discourse | discourse | <2025.12.2 | / | / | / | / | / | / | |
| a | discourse | discourse | <2026.1.1 | / | / | / | / | / | / | |
| a | discourse | discourse | <2026.2.0 | / | / | / | / | / | / |
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: NETWORK
- Attack Complexity: LOW
- Privileges Required: LOW
- Scope: UNCHANGED
- Confidentiality Impact: NONE
- Integrity Impact: LOW
- Availability Impact: NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Timeline
Published: Feb. 26, 2026, 8:31 p.m.
Last Modified: Feb. 27, 2026, 2:06 p.m.
Last Modified: Feb. 27, 2026, 2:06 p.m.
Status : Awaiting Analysis
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.