{"id":"CVE-2026-49256","state":"PUBLISHED","title":"Discourse: Hidden tag names leaked via category serializers","description":"Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowed_tags, allowed_tag_groups, or required tag groups could leak to anonymous and unauthorized users through category and group endpoints. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.","publishedAt":"2026-07-09T21:56:40.444Z","updatedAt":"2026-07-10T13:39:27.829Z","severity":{"score":6.3,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/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, < 2026.1.5","status":"affected"},{"version":">= 2026.4.0-latest, < 2026.4.2","status":"affected"},{"version":">= 2026.5.0-latest, < 2026.5.1","status":"affected"}]}],"references":["https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx","https://github.com/discourse/discourse/releases/tag/v2026.1.5","https://github.com/discourse/discourse/releases/tag/v2026.4.2","https://github.com/discourse/discourse/releases/tag/v2026.5.1","https://github.com/discourse/discourse/releases/tag/v2026.6.0"],"weaknesses":["CWE-200"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/49xxx/CVE-2026-49256.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-49256","state":"PUBLISHED","datePublished":"2026-07-09T21:56:40.444Z","dateUpdated":"2026-07-10T13:39:27.829Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-28T14:33:01.179Z"},"containers":{"cna":{"title":"Discourse: Hidden tag names leaked via category serializers","descriptions":[{"lang":"en","value":"Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowed_tags, allowed_tag_groups, or required tag groups could leak to anonymous and unauthorized users through category and group endpoints. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5."}],"affected":[{"vendor":"discourse","product":"discourse","versions":[{"version":">= 2026.1.0-latest, < 2026.1.5","status":"affected"},{"version":">= 2026.4.0-latest, < 2026.4.2","status":"affected"},{"version":">= 2026.5.0-latest, < 2026.5.1","status":"affected"}]}],"references":[{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx","name":"https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/discourse/discourse/releases/tag/v2026.1.5","name":"https://github.com/discourse/discourse/releases/tag/v2026.1.5","tags":["x_refsource_MISC"]},{"url":"https://github.com/discourse/discourse/releases/tag/v2026.4.2","name":"https://github.com/discourse/discourse/releases/tag/v2026.4.2","tags":["x_refsource_MISC"]},{"url":"https://github.com/discourse/discourse/releases/tag/v2026.5.1","name":"https://github.com/discourse/discourse/releases/tag/v2026.5.1","tags":["x_refsource_MISC"]},{"url":"https://github.com/discourse/discourse/releases/tag/v2026.6.0","name":"https://github.com/discourse/discourse/releases/tag/v2026.6.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-200","lang":"en","description":"CWE-200: Exposure of Sensitive Information to an Unauthorized Actor","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-09T21:56:40.444Z"},"source":{"advisory":"GHSA-mwp7-572g-6qpx","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-10T13:39:15.102132Z","id":"CVE-2026-49256","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":"2026-07-10T13:39:27.829Z"}}]}}}