{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-27570", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-02-20T17:40:28.448Z", "datePublished": "2026-03-19T20:52:17.572Z", "dateUpdated": "2026-03-19T20:52:17.572Z"}, "containers": {"cna": {"title": "Discourse Vulnerable to Stored XSS via Shared AI Conversation Onebox", "problemTypes": [{"descriptions": [{"cweId": "CWE-79", "lang": "en", "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 5.1, "baseSeverity": "MEDIUM", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N", "version": "4.0"}}], "references": [{"name": "https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv"}, {"name": "https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1", "tags": ["x_refsource_MISC"], "url": "https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1"}, {"name": "https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1", "tags": ["x_refsource_MISC"], "url": "https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1"}, {"name": "https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc", "tags": ["x_refsource_MISC"], "url": "https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc"}], "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": "2026-03-19T20:52:17.572Z"}, "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, the onebox method in the SharedAiConversation model renders the conversation title directly into HTML without proper sanitization. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, tighten access by changing the `ai_bot_public_sharing_allowed_groups` site setting."}], "source": {"advisory": "GHSA-hfxw-89hw-vwmv", "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, the onebox method in the SharedAiConversation model renders the conversation title directly into HTML without proper sanitization. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, tighten access by changing the `ai_bot_public_sharing_allowed_groups` site setting."}], "id": "CVE-2026-27570", "lastModified": "2026-03-20T13:39:46.493", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 5.1, "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": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/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": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-03-19T21:17:09.250", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1"}, {"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1"}, {"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc"}, {"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Undergoing Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-79"}], "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": "2026-03-19T22:51:37.026518+00:00", "value": {"mitigation_remediation": ["Update Discourse to version 2026.3.0\u2011latest.1 or later (2026.2.1 and 2026.1.2 also contain the patch).", "If an update is not yet possible, restrict public sharing by configuring the ai_bot_public_sharing_allowed_groups site setting to limit which user groups can share AI conversations."], "summary": {"action": "Apply Patch", "impact": "Stored XSS"}, "threat_synthesis": {"affected_systems": "The vulnerable product is Discourse (discourse:discourse). Versions before 2026.3.0\u2011latest.1, 2026.2.1, and 2026.1.2 are affected. These releases embed the conversation title unsanitized; newer releases contain a patch.", "description_and_impact": "Discourse is an open\u2011source discussion platform. The identified flaw is a stored cross\u2011site scripting vulnerability caused by the onebox method in the SharedAiConversation model rendering the conversation title directly into HTML without proper sanitization. This allows malicious HTML or script to be stored and subsequently executed in any browser that renders the conversation, as the title is inserted unescaped.", "risk_and_exploitability": "The CVSS score is 5.1, indicating moderate severity. The EPSS score is unavailable and the vulnerability is not listed in the CISA KEV catalog, suggesting no widespread exploitation reported. Exploitation requires the capability to set or modify the title of a Shared AI conversation; once the title contains malicious content, any user who views the conversation will receive that content rendered by the browser."}}}}, "created": "2026-03-20T08:56:07.247203+00:00", "updated": "2026-03-20T11:06:17.160522+00:00", "vendors": ["discourse", "discourse$PRODUCT$discourse"]}