{"id":"CVE-2026-49256","summary":"Discourse: Hidden tag names leaked via category serializers","details":"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.","aliases":["BIT-discourse-2026-49256","GHSA-mwp7-572g-6qpx"],"modified":"2026-10-28T02:31:05.741683367Z","published":"2026-07-09T21:56:40.444Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-200"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49256.json"},"references":[{"type":"WEB","url":"https://github.com/discourse/discourse/releases/tag/v2026.1.5"},{"type":"WEB","url":"https://github.com/discourse/discourse/releases/tag/v2026.4.2"},{"type":"WEB","url":"https://github.com/discourse/discourse/releases/tag/v2026.5.1"},{"type":"WEB","url":"https://github.com/discourse/discourse/releases/tag/v2026.6.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49256.json"},{"type":"ADVISORY","url":"https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49256"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/discourse/discourse","events":[{"introduced":"322d3c0ac6a8f133b3f82875e9dbbe310f638c1b"},{"fixed":"c06899647d758493d95a5b301e573ffa3db1e878"},{"introduced":"fdd750d960e603415db62242eca3c30d68e366db"},{"fixed":"4bbdddfc6700ca23604242111d4fa0e00347af97"},{"introduced":"640840d818f4ee9375829ece0ef452923bb0c012"},{"fixed":"598586ccf2e046a25d4b54132e4e1feb47f24e98"},{"introduced":"06d03da34c4ed09ea59f917f045ba250d2b6320d"},{"fixed":"06d03da34c4ed09ea59f917f045ba250d2b6320d"}],"database_specific":{"extracted_events":[{"range":[{"introduced":"2026.1.0"},{"fixed":"2026.1.5"}],"source":"CPE_RANGE","cpe":"cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*"},{"cpe":"cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*","range":[{"introduced":"2026.4.0"},{"fixed":"2026.4.2"}],"source":"CPE_RANGE"},{"cpe":"cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*","range":[{"introduced":"2026.5.0"},{"fixed":"2026.5.1"}],"source":"CPE_RANGE"},{"cpe":"cpe:2.3:a:discourse:discourse:2026.6.0:*:*:*:latest:*:*:*","range":[{"introduced":"2026.6.0"},{"last_affected":"2026.6.0"}],"source":"CPE_STRING"},{"source":"REFERENCES_TAG","original_tag":"v2026.1.5","range":[{"fixed":"c06899647d758493d95a5b301e573ffa3db1e878"}]},{"original_tag":"v2026.4.2","range":[{"fixed":"4bbdddfc6700ca23604242111d4fa0e00347af97"}],"source":"REFERENCES_TAG"},{"original_tag":"v2026.5.1","range":[{"fixed":"598586ccf2e046a25d4b54132e4e1feb47f24e98"}],"source":"REFERENCES_TAG"},{"original_tag":"v2026.6.0","range":[{"fixed":"06d03da34c4ed09ea59f917f045ba250d2b6320d"}],"source":"REFERENCES_TAG"}]}}],"versions":["2026.6.0","v2026.5.0","v2026.1.4","v2026.4.1","v2026.5.0-latest.1","v2026.4.0","v2026.5.0-latest","v2026.1.3","v2026.4.0-latest","v2026.1.2","v2026.1.1","v2026.1.0","stable","esr","v2026.1.0-latest"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49256.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V4","score":"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"}]}