CVE-2026-28227 PUBLISHED

Discourse Vulnerable to Unauthorized Topic Creation in Staff-Only Categories via Topic Timer publish_to_category

Assigner: GitHub_M
Reserved: 25.02.2026 Published: 26.02.2026 Updated: 26.02.2026

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, TL4 users can publish topics into staff-only categories via the publish_to_category topic timer, bypassing authorization checks. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U
CVSS Score: 1.2

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	High
User Interaction	None

CVSS 4.0

Product Status

Vendor	discourse
Product	discourse
Versions	Version < 2025.12.2 is affected Version >= 2026.1.0-latest, < 2026.1.1 is affected Version >= 2026.2.0-latest, < 2026.2.0 is affected

References

https://github.com/discourse/discourse/security/advisories/GHSA-m49w-78mh-87jp

Problem Types

CWE-863: Incorrect Authorization CWE