{"id":"CVE-2026-27570","state":"PUBLISHED","title":"Discourse Vulnerable to Stored XSS via Shared AI Conversation Onebox","description":"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.","publishedAt":"2026-03-19T20:52:17.572Z","updatedAt":"2026-03-24T19:43:07.713Z","severity":{"score":5.1,"label":"Medium","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["discourse discourse"],"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"}]}],"references":["https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv","https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1","https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1","https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:11:31.369Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/27xxx/CVE-2026-27570.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-27570","state":"PUBLISHED","datePublished":"2026-03-19T20:52:17.572Z","dateUpdated":"2026-03-24T19:43:07.713Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-02-20T17:40:28.448Z"},"containers":{"cna":{"title":"Discourse Vulnerable to Stored XSS via Shared AI Conversation Onebox","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."}],"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"}]}],"references":[{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv","name":"https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1","name":"https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1","tags":["x_refsource_MISC"]},{"url":"https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1","name":"https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1","tags":["x_refsource_MISC"]},{"url":"https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc","name":"https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc","tags":["x_refsource_MISC"]}],"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-03-19T20:52:17.572Z"},"source":{"advisory":"GHSA-hfxw-89hw-vwmv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-24T19:32:54.719699Z","id":"CVE-2026-27570","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-03-24T19:43:07.713Z"}}]}}}