CVE-2026-23743

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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."}, {"lang": "es", "value": "Discourse es una plataforma de discusi\u00f3n de c\u00f3digo abierto. En versiones anteriores a la 3.5.4, 2025.11.2, 2025.12.1 y 2026.1.0, los enlaces permanentes que apuntaban a recursos de acceso restringido (temas privados, categor\u00edas, publicaciones o etiquetas ocultas) redirig\u00edan a los usuarios a URLs que conten\u00edan el slug del recurso, incluso cuando el usuario no ten\u00eda acceso para ver el recurso. Esto filtraba informaci\u00f3n potencialmente sensible (p. ej., t\u00edtulos de temas privados) a trav\u00e9s del encabezado Location de la redirecci\u00f3n y el cuadro de b\u00fasqueda de la p\u00e1gina 404. Este problema est\u00e1 parcheado en las versiones 3.5.4, 2025.11.2, 2025.12.1 y 2026.1.0. No hay soluciones alternativas conocidas disponibles."}], "id": "CVE-2026-23743", "lastModified": "2026-06-17T10:22:02.050", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.9, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-23743", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-01-28T20:52:39.923679Z", "version": "2.0.3"}}]}, "published": "2026-01-28T21:16:11.597", "references": [{"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://github.com/discourse/discourse/security/advisories/GHSA-v5jw-rxc6-4cvv"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-200"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"analysis": {"en": {"generated_at": "2026-04-18T01:40:26.496569+00:00", "value": {"mitigation_remediation": ["Upgrade Discourse to a patched release (3.5.4, 2025.11.2, 2025.12.1, 2026.1.0 or later).", "Configure the system to enforce strict authorization checks on permalink generation so that only users with access receive the resource slug.", "Modify redirect handling so that requests for restricted resources that lack the proper permissions result in a 403 or 404 response without revealing slugs in the Location header or on the 404 page."], "summary": {"action": "Apply Patch", "impact": "Information Disclosure"}, "threat_synthesis": {"affected_systems": "Discourse, the open\u2011source discussion platform, is vulnerable in releases before 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0; any instance running those versions is impacted.", "description_and_impact": "Permalinks that target access\u2011restricted resources in Discourse redirect users to URLs containing the resource slug, even when the user lacks permission. The redirect Location header and the 404 page\u2019s search box expose potentially sensitive information such as private topic titles or tags. The flaw is an information\u2011disclosure vulnerability (CWE\u2011200).", "risk_and_exploitability": "The CVSS score of 6.9 indicates medium severity, while the EPSS score of less than 1% means exploitation is unlikely at present. The vulnerability is not listed in CISA\u2019s KEV catalog. An attacker can craft a permalink or observe a legitimate link and trigger a redirect that exposes the slug, revealing sensitive identifiers to unauthenticated or unauthorized users. The attack vector is web\u2011based, requiring only the ability to access the permalink URL."}}}}, "created": "2026-01-29T09:08:54.501736+00:00", "updated": "2026-04-18T01:45:33.401663+00:00", "vendors": ["discourse", "discourse$PRODUCT$discourse"]}