{"id":"CVE-2021-32659","details":"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.","aliases":["GHSA-35g4-qx3c-vjhx"],"modified":"2026-07-08T06:29:07.438666364Z","published":"2021-06-16T19:15:38.830Z","database_specific":{},"references":[{"type":"ADVISORY","url":"https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-35g4-qx3c-vjhx"},{"type":"FIX","url":"https://github.com/matrix-org/matrix-appservice-bridge/commit/b69e745584a34fcfd858df33e4631e420da07b9f"},{"type":"FIX","url":"https://github.com/matrix-org/matrix-appservice-bridge/releases/tag/2.6.1"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/matrix-org/matrix-appservice-bridge","events":[{"introduced":"0"},{"fixed":"7e32516a211b9d13433fc5a6016642e3ad2fc974"},{"fixed":"b69e745584a34fcfd858df33e4631e420da07b9f"}],"database_specific":{"source":["CPE_RANGE","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"2.6.1"}],"cpe":"cpe:2.3:a:matrix:matrix-appservice-bridge:*:*:*:*:*:node.js:*:*"}}],"versions":["2.6.0","2.6.0-rc1","2.5.0","v2.5.0-rc1","2.4.0","2.4.0-rc2","2.4.0-rc1","2.3.1","2.3.0","2.3.0-rc3","2.3.0-rc2","2.3.0-rc1","2.2.0","2.2.0-rc2","2.2.0-rc1","2.1.0","2.1.0-rc2","2.1.0-rc1","2.0.0","v1.13.2","1.13.1","1.13.0","1.12.2","1.12.1","1.12.0","1.11.1","1.11.0","1.10.2","1.10.0","1.7.0","1.6.0c","1.6.0b","1.6.0a","1.6.0","1.4.0a","1.4.0","1.3.0","1.2.1","1.1.1","1.0.1","1.0.0","0.3.6","0.3.5","0.3.4","0.3.3","0.3.2","0.1.5","0.1.4","0.1.3","0.1.2","0.1.1","0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-32659.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N"}]}