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1.2

Discourse: Malicious users can post in staff-only categories.

CVE-2026-28227
Summary

Prior to certain Discourse versions, a security issue allowed malicious users to post in restricted categories. This has been fixed in versions 2025.12.2, 2026.1.1, and 2026.2.0, so upgrade to one of these versions to protect your site.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software
VendorProductAffected versionsFix available
discourse discourse <= 2025.12.2
discourse discourse > 2026.1.0 , <= 2026.1.1
discourse discourse 2026.2.0
Original title
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 tim...
Original 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.
nvd CVSS3.1 2.7
nvd CVSS4.0 1.2
Vulnerability type
CWE-863 Incorrect Authorization
Published: 26 Feb 2026 · Updated: 12 Mar 2026 · First seen: 6 Mar 2026