Is there a patch available for EUVD-2026-18866?

Yes, a patch is available for EUVD-2026-18866. Update the affected software to the latest version immediately.

Discourse EUVD-2026-18866

Q: What is the CVSS score of EUVD-2026-18866?

EUVD-2026-18866 has a CVSS 4.0 base score of 6.3 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

| CVE-2026-27481 MEDIUM

Information Exposure (CWE-200)

2026-04-03 GitHub_M

Information Disclosure Discourse

6.3

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.3 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Patch available

Apr 16, 2026 - 05:29 EUVD

2026.2.2,2026.1.3,2026.3.0

EUVD ID Assigned

Apr 03, 2026 - 22:15 euvd

EUVD-2026-18866

Analysis Generated

Apr 03, 2026 - 22:15 vuln.today

CVE Published

Apr 03, 2026 - 21:27 nvd

MEDIUM 6.3

DescriptionGitHub Advisory

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authorization bypass vulnerability allows unauthenticated or unauthorized users to view hidden (staff-only) tags and its associated data. All Discourse instances with tagging enabled and staff-only tag groups configured are impacted. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

AnalysisAI

Discourse versions 2026.1.0-2026.1.2, 2026.2.0-2026.2.1, and 2026.3.0-pre allow unauthenticated users to enumerate and view hidden staff-only tags and associated metadata through an authorization bypass flaw. All instances with tagging enabled and staff-only tag groups configured are vulnerable. …

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Vulnerability AssessmentAI

Risk Assessment	The CVSS v4.0 score of 6.3 reflects low confidentiality impact (VC:L) with network-based unauthenticated access (AV:N, PR:N) and low attack complexity (AC:L), though an attack requires prior timing (AT:P). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	An unauthenticated attacker accessing a Discourse forum discovers the existence and metadata of staff-only tags by making repeated API requests or leveraging tag enumeration endpoints, which fail to validate authorization due to the bypass flaw. The attacker gains intelligence about restricted discussion topics (e.g., 'internal-incident', 'executive-team') without needing community credentials, potentially enabling social engineering or directing further reconnaissance toward sensitive organizational areas. …
Remediation	Vendor-released patches are available in Discourse versions 2026.1.3, 2026.2.2, and 2026.3.0 (final). … Detailed patch versions, workarounds, and compensating controls in full report.

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EUVD-2026-18866 vulnerability details – vuln.today

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