{"api_version":"1","generated_at":"2026-04-23T08:51:57+00:00","cve":"CVE-2021-32659","urls":{"html":"https://cve.report/CVE-2021-32659","api":"https://cve.report/api/cve/CVE-2021-32659.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-32659","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-32659"},"summary":{"title":"CVE-2021-32659","description":"Matrix-appservice-bridge is the bridging service for the Matrix communication program's application services. In versions 2.6.0 and earlier, if a bridge has room upgrade handling turned on in the configuration (the `roomUpgradeOpts` key when instantiating a new `Bridge` instance.), any `m.room.tombstone` event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room `m.room.create` event is not checked to verify if the `predecessor` field contains the previous room. This means that any malicious admin of a bridged room can repoint the traffic to a different room without the new room being aware. Versions 2.6.1 and greater are patched. As a workaround, disabling the automatic room upgrade handling can be done by removing the `roomUpgradeOpts` key from the `Bridge` class options.","state":"PUBLIC","assigner":"security-advisories@github.com","published_at":"2021-06-16 19:15:00","updated_at":"2021-07-09 19:46:00"},"problem_types":["CWE-306"],"metrics":[],"references":[{"url":"https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-35g4-qx3c-vjhx","name":"https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-35g4-qx3c-vjhx","refsource":"CONFIRM","tags":[],"title":"Automatic room upgrade handling can be used maliciously to bridge a room non-consentually  · Advisory · matrix-org/matrix-appservice-bridge · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/matrix-org/matrix-appservice-bridge/commit/b69e745584a34fcfd858df33e4631e420da07b9f","name":"https://github.com/matrix-org/matrix-appservice-bridge/commit/b69e745584a34fcfd858df33e4631e420da07b9f","refsource":"MISC","tags":[],"title":"Check m.room.create event on room upgrade · matrix-org/matrix-appservice-bridge@b69e745 · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/matrix-org/matrix-appservice-bridge/releases/tag/2.6.1","name":"https://github.com/matrix-org/matrix-appservice-bridge/releases/tag/2.6.1","refsource":"MISC","tags":[],"title":"Release 2.6.1 (2021-06-02) · matrix-org/matrix-appservice-bridge · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-32659","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32659","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2021","cve_id":"32659","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"matrix","cpe5":"matrix-appservice-bridge","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"node.js","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[{"cve":"CVE-2021-32659","qid":"982090","title":"Nodejs (npm) Security Update for matrix-appservice-bridge (GHSA-35g4-qx3c-vjhx)"}]},"source_records":{"cve_program":{"CVE_data_meta":{"ASSIGNER":"security-advisories@github.com","ID":"CVE-2021-32659","STATE":"PUBLIC","TITLE":"Automatic room upgrade handling can be used maliciously to bridge a room non-consentually "},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"matrix-appservice-bridge","version":{"version_data":[{"version_value":"< 2.6.1"}]}}]},"vendor_name":"matrix-org"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"Matrix-appservice-bridge is the bridging service for the Matrix communication program's application services. In versions 2.6.0 and earlier, if a bridge has room upgrade handling turned on in the configuration (the `roomUpgradeOpts` key when instantiating a new `Bridge` instance.), any `m.room.tombstone` event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room `m.room.create` event is not checked to verify if the `predecessor` field contains the previous room. This means that any malicious admin of a bridged room can repoint the traffic to a different room without the new room being aware. Versions 2.6.1 and greater are patched. As a workaround, disabling the automatic room upgrade handling can be done by removing the `roomUpgradeOpts` key from the `Bridge` class options."}]},"impact":{"cvss":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-306: Missing Authentication for Critical Function"}]}]},"references":{"reference_data":[{"name":"https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-35g4-qx3c-vjhx","refsource":"CONFIRM","url":"https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-35g4-qx3c-vjhx"},{"name":"https://github.com/matrix-org/matrix-appservice-bridge/commit/b69e745584a34fcfd858df33e4631e420da07b9f","refsource":"MISC","url":"https://github.com/matrix-org/matrix-appservice-bridge/commit/b69e745584a34fcfd858df33e4631e420da07b9f"},{"name":"https://github.com/matrix-org/matrix-appservice-bridge/releases/tag/2.6.1","refsource":"MISC","url":"https://github.com/matrix-org/matrix-appservice-bridge/releases/tag/2.6.1"}]},"source":{"advisory":"GHSA-35g4-qx3c-vjhx","discovery":"UNKNOWN"}},"nvd":{"publishedDate":"2021-06-16 19:15:00","lastModifiedDate":"2021-07-09 19:46:00","problem_types":["CWE-306"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE","baseScore":4.9,"baseSeverity":"MEDIUM"},"exploitabilityScore":1.2,"impactScore":3.6},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:M/Au:S/C:N/I:P/A:N","accessVector":"NETWORK","accessComplexity":"MEDIUM","authentication":"SINGLE","confidentialityImpact":"NONE","integrityImpact":"PARTIAL","availabilityImpact":"NONE","baseScore":3.5},"severity":"LOW","exploitabilityScore":6.8,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:matrix:matrix-appservice-bridge:*:*:*:*:*:node.js:*:*","versionEndExcluding":"2.6.1","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"32659","Ordinal":"208047","Title":"CVE-2021-32659","CVE":"CVE-2021-32659","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"32659","Ordinal":"1","NoteData":"Matrix-appservice-bridge is the bridging service for the Matrix communication program's application services. In versions 2.6.0 and earlier, if a bridge has room upgrade handling turned on in the configuration (the `roomUpgradeOpts` key when instantiating a new `Bridge` instance.), any `m.room.tombstone` event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room `m.room.create` event is not checked to verify if the `predecessor` field contains the previous room. This means that any malicious admin of a bridged room can repoint the traffic to a different room without the new room being aware. Versions 2.6.1 and greater are patched. As a workaround, disabling the automatic room upgrade handling can be done by removing the `roomUpgradeOpts` key from the `Bridge` class options.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"32659","Ordinal":"2","NoteData":"2021-06-16","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"32659","Ordinal":"3","NoteData":"2021-06-16","Type":"Other","Title":"Modified"}]}}}