CVE-2021-32659 | Date: (C)2021-06-17 (M)2023-12-22 |
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.
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 4.9 | CVSS Score : 3.5 |
Exploit Score: 1.2 | Exploit Score: 6.8 |
Impact Score: 3.6 | Impact Score: 2.9 |
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CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: NETWORK | Access Vector: NETWORK |
Attack Complexity: LOW | Access Complexity: MEDIUM |
Privileges Required: HIGH | Authentication: SINGLE |
User Interaction: NONE | Confidentiality: NONE |
Scope: UNCHANGED | Integrity: PARTIAL |
Confidentiality: NONE | Availability: NONE |
Integrity: HIGH | |
Availability: NONE | |
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