CVE-2026-27454

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{"affected": [{"affectedData": [{"product": "discourse", "vendor": "discourse", "versions": [{"status": "affected", "version": ">= 2026.1.0-latest, < 2026.1.2"}, {"status": "affected", "version": ">= 2026.2.0-latest, < 2026.2.1"}, {"status": "affected", "version": "= 2026.3.0-latest"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "matchCriteriaId": "4BE96625-3609-410C-B41E-4A824C1A57C0", "versionEndExcluding": "2026.1.2", "versionStartIncluding": "2026.1.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "matchCriteriaId": "FD31CF04-CF2F-4FB9-8880-9243BC7671A7", "versionEndExcluding": "2026.2.1", "versionStartIncluding": "2026.2.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*", "matchCriteriaId": "E3FE9277-4F6B-4FD0-991F-F0FB8D226E1C", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, requesting /posts/:id.json?version=X bypassed authorization checks on post revisions. The display_post method called post.revert_to directly without verifying whether the revision was hidden or if the user had permission to view edit history. This meant hidden revisions (intentionally concealed by staff) could be read by any user by simply enumerating version numbers. Starting in versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, Discourse looks up the PostRevision and call guardian.ensure_can_see! before reverting, consistent with how the /posts/:id/revisions/:revision endpoint already authorizes access. No known workarounds are available."}, {"lang": "es", "value": "Discourse es una plataforma de discusi\u00f3n de c\u00f3digo abierto. Antes de las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2, solicitar /posts/:id.json?version=X elud\u00eda las comprobaciones de autorizaci\u00f3n en las revisiones de publicaciones. El m\u00e9todo display_post llamaba a post.revert_to directamente sin verificar si la revisi\u00f3n estaba oculta o si el usuario ten\u00eda permiso para ver el historial de edici\u00f3n. Esto significaba que las revisiones ocultas (ocultadas intencionadamente por el personal) pod\u00edan ser le\u00eddas por cualquier usuario simplemente enumerando los n\u00fameros de versi\u00f3n. A partir de las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2, Discourse busca la PostRevision y llama a guardian.ensure_can_see! antes de revertir, de forma consistente con c\u00f3mo el endpoint /posts/:id/revisions/:revision ya autoriza el acceso. No se conocen soluciones alternativas disponibles."}], "id": "CVE-2026-27454", "lastModified": "2026-06-17T10:27:10.910", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-27454", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-03-20T17:10:07.787373Z", "version": "2.0.3"}}]}, "published": "2026-03-19T21:17:08.920", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/discourse/discourse/commit/8510fde30eb0d7f2dee822a95f6cf43b9ac943d0"}, {"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/discourse/discourse/commit/c0eeb5892f5d61ad62b057f4d468333a6e9f28c3"}, {"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/discourse/discourse/commit/c474fbd79d2bd231baafb4332970297d781f92ca"}, {"source": "security-advisories@github.com", "tags": ["Vendor Advisory"], "url": "https://github.com/discourse/discourse/security/advisories/GHSA-fq69-f929-wp96"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-862"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2026.1.0-latest,2026.1.2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2026.2.0-latest,2026.2.1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2026.3.0-latest"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "discourse", "source": "cna", "vendor": "discourse"}, "product": "discourse", "vendor": "discourse"}], "analysis": {"en": {"generated_at": "2026-03-25T03:26:01.105871+00:00", "value": {"mitigation_remediation": ["Upgrade to Discourse 2026.3.0\u2011latest.1, 2026.2.1, or 2026.1.2 or newer to enable the guardian.ensure_can_see! check"], "summary": {"action": "Patch", "impact": "Authorization Bypass Allowing Hidden Post Revision Disclosure"}, "threat_synthesis": {"affected_systems": "Vulnerable for all Discourse releases older than 2026.3.0\u2011latest.1, 2026.2.1, and 2026.1.2. The platform is the open\u2011source forum software Discourse.", "description_and_impact": "Discourse allows a user to read any hidden post revision via the /posts/:id.json?version path before certain releases. The endpoint bypasses checks that should enforce visibility, so staff\u2011hidden patches can be exposed to anyone who has access to the forum. This provides indirect confidentiality breach of content intended to remain internal.", "risk_and_exploitability": "CVSS 5.3 indicates moderate severity; EPSS <1% suggests low exploitation probability and it is not in CISA KEV. The issue is exploitable via a simple HTTP GET against the affected endpoint, requiring only knowledge of the post ID and a revision number. Because the system does not enforce visibility, any user who can enumerate revisions can read content that should be hidden, posing a confidentiality risk for staff\u2011sanctioned edits."}}}}, "created": "2026-03-20T08:56:10.733056+00:00", "updated": "2026-03-25T11:54:58.284572+00:00", "vendors": ["discourse", "discourse$PRODUCT$discourse"]}