{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-27454", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-02-19T17:25:31.100Z", "datePublished": "2026-03-19T20:39:28.350Z", "dateUpdated": "2026-03-19T20:39:28.350Z"}, "containers": {"cna": {"title": "Discourse has check revision visibility on posts endpoint", "problemTypes": [{"descriptions": [{"cweId": "CWE-862", "lang": "en", "description": "CWE-862: Missing Authorization", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"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"}}], "references": [{"name": "https://github.com/discourse/discourse/security/advisories/GHSA-fq69-f929-wp96", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/discourse/discourse/security/advisories/GHSA-fq69-f929-wp96"}, {"name": "https://github.com/discourse/discourse/commit/8510fde30eb0d7f2dee822a95f6cf43b9ac943d0", "tags": ["x_refsource_MISC"], "url": "https://github.com/discourse/discourse/commit/8510fde30eb0d7f2dee822a95f6cf43b9ac943d0"}, {"name": "https://github.com/discourse/discourse/commit/c0eeb5892f5d61ad62b057f4d468333a6e9f28c3", "tags": ["x_refsource_MISC"], "url": "https://github.com/discourse/discourse/commit/c0eeb5892f5d61ad62b057f4d468333a6e9f28c3"}, {"name": "https://github.com/discourse/discourse/commit/c474fbd79d2bd231baafb4332970297d781f92ca", "tags": ["x_refsource_MISC"], "url": "https://github.com/discourse/discourse/commit/c474fbd79d2bd231baafb4332970297d781f92ca"}], "affected": [{"vendor": "discourse", "product": "discourse", "versions": [{"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", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-19T20:39:28.350Z"}, "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."}], "source": {"advisory": "GHSA-fq69-f929-wp96", "discovery": "UNKNOWN"}}}}

{}

{"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."}], "id": "CVE-2026-27454", "lastModified": "2026-03-20T13:39:46.493", "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"}]}, "published": "2026-03-19T21:17:08.920", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/commit/8510fde30eb0d7f2dee822a95f6cf43b9ac943d0"}, {"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/commit/c0eeb5892f5d61ad62b057f4d468333a6e9f28c3"}, {"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/commit/c474fbd79d2bd231baafb4332970297d781f92ca"}, {"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/security/advisories/GHSA-fq69-f929-wp96"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Undergoing Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-862"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"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": "2026-03-19T22:27:23.159440+00:00", "value": {"mitigation_remediation": ["Apply the latest Discourse patch (e.g., upgrade to 2026.3.0\u2011latest.1 or newer versions).", "Verify that the /posts/:id.json?version= endpoint no longer returns hidden revisions for regular users."], "summary": {"action": "Apply Patch", "impact": "Unauthorized access to hidden post revisions"}, "threat_synthesis": {"affected_systems": "Discourse platform, specifically all versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2. Users of these releases are at risk if they expose hidden revisions through enumeration of version numbers.", "description_and_impact": "The vulnerability allows any user to retrieve hidden post revisions by passing a version parameter to the /posts/:id.json endpoint, bypassing authorization checks that govern whether a revision is hidden or whether the user can view edit history. This results in a confidentiality breach without privilege escalation, as no elevated rights are required. The weakness is an authorization flaw (CWE-862).", "risk_and_exploitability": "The CVSS score of 5.3 indicates medium severity. An attacker can exploit the flaw remotely via normal HTTP requests without needing special credentials or additional vulnerabilities. EPSS data is unavailable and the vulnerability is not listed in KEV, suggesting moderate exploitation likelihood. Since hidden revisions are maintained by staff and are intended as confidential, the impact on confidentiality could be significant if sensitive information is stored."}}}}, "created": "2026-03-20T08:56:10.733056+00:00", "updated": "2026-03-20T11:06:20.756774+00:00", "vendors": ["discourse", "discourse$PRODUCT$discourse"]}