CVE-2026-28227Network attack vector

Restricted topic publishing via unchecked topic timer

Published Feb 26, 2026 · Updated Feb 26, 2026

Incorrect authorization in Discourse allows remote authenticated users to publish topics in staff-only categories through a topic timer. The publish_to_category topic timer accepts a staff-only destination from TL4 users without enforcing the category authorization required for direct publishing. Trust Level 4 access is required, and the consequence is limited to unauthorized topic creation, with no reported confidentiality or availability impact.

CVSS severity5.1
Medium
EPSS probability2.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Discourse allows remote authenticated users to publish topics in staff-only categories through a topic timer. The publish_to_category topic timer accepts a staff-only destination from TL4 users without enforcing the category authorization required for direct publishing. Trust Level 4 access is required, and the consequence is limited to unauthorized topic creation, with no reported confidentiality or availability impact.

The record

CVE
CVE-2026-28227
Published
Feb 26, 2026
Updated
Feb 26, 2026
Vendor
Discourse
Product
Discourse
Classifications
CWE-863
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2025.12.2
  2. Affected versionversion=>= 2026.1.0-latest, < 2026.1.1
  3. Affected versionversion=>= 2026.2.0-latest, < 2026.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Discourse · Discourseversion=< 2025.12.2; version=>= 2026.1.0-latest, < 2026.1.1; version=>= 2026.2.0-latest, < 2026.2.0

Published CVSS scores

1.2GitHub, Inc.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
5.1GitHub, Inc.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
2.7NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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