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Discourse CVE-2026-23743

HIGH
Information Exposure (CWE-200)
2026-01-28 security-advisories@github.com
7.5
CVSS 3.1 · GitHub Advisory
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Severity by source

GitHub Advisory PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

2
Analysis Generated
Mar 12, 2026 - 21:54 vuln.today
CVE Published
Jan 28, 2026 - 21:16 nvd
HIGH 7.5

DescriptionGitHub Advisory

Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, permalinks pointing to access-restricted resources (private topics, categories, posts, or hidden tags) were redirecting users to URLs containing the resource slug, even when the user didn't have access to view the resource. This leaked potentially sensitive information (e.g., private topic titles) via the redirect Location header and the 404 page's search box. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. No known workarounds are available.

AnalysisAI

Discourse is an open source discussion platform. [CVSS 7.5 HIGH]

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Access permalink to restricted resource
Exploit
Server redirects with resource slug in Location header
Impact
Attacker reads sensitive topic title from redirect

Vulnerability AssessmentAI

Exploitation Discourse instance with access-restricted resources (private topics, categories, posts, or hidden tags). … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment CVSS 7.5 (HIGH). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario An attacker could exploit this vulnerability to compromise the affected system.
Remediation Monitor vendor advisories for a patch. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours: Inventory all Discourse deployments and confirm affected versions; disable public access to Discourse instances if feasible. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

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CVE-2026-23743 vulnerability details – vuln.today

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