Low severity · published Feb 26, 2026
CVE-2026-28227
Discourse Vulnerable to Unauthorized Topic Creation in Staff-Only Categories via Topic Timer publish_to_category
2.7
CVSS
3.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)3.3% · higher than 88% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DI
discourse · discourse
< 2025.12.2; >= 2026.1.0-latest, < 2026.1.1; >= 2026.2.0-latest, < 2026.2.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-28227
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-28227
Vendor Advisory
https://github.com/discourse/discourse/security/advisories/GHSA-m49w-78mh-87jp
More from discourse
9.9
CVE-2025-68662
FinalDestination hostname matching allows SSRF protection bypass
9.8
CVE-2025-53102
Discourse's WebAuthn challenge isn't cleared from user session after authentication
9.8
CVE-2025-48877
Discourse is an open-source discussion platform
9.8
CVE-2023-47121
Discourse is an open source platform for community discussion
9.8
CVE-2021-41163
Discourse is an open source platform for community discussion