CVE-2022-39249 | Date: (C)2022-09-30 (M)2023-12-22 |
Matrix Javascript SDK is the Matrix Client-Server SDK for JavaScript. Prior to version 19.7.0, an attacker cooperating with a malicious homeserver can construct messages appearing to have come from another person. Such messages will be marked with a grey shield on some platforms, but this may be missing in others. This attack is possible due to the matrix-js-sdk implementing a too permissive key forwarding strategy on the receiving end. Starting with version 19.7.0, the default policy for accepting key forwards has been made more strict in the matrix-js-sdk. matrix-js-sdk will now only accept forwarded keys in response to previously issued requests and only from own, verified devices. The SDK now sets a `trusted` flag on the decrypted message upon decryption, based on whether the key used to decrypt the message was received from a trusted source. Clients need to ensure that messages decrypted with a key with `trusted = false` are decorated appropriately, for example, by showing a warning for such messages. This attack requires coordination between a malicious homeserver and an attacker, and those who trust your homeservers do not need a workaround.
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 7.5 | CVSS Score : |
Exploit Score: 3.9 | Exploit Score: |
Impact Score: 3.6 | Impact Score: |
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CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: NETWORK | Access Vector: |
Attack Complexity: LOW | Access Complexity: |
Privileges Required: NONE | Authentication: |
User Interaction: NONE | Confidentiality: |
Scope: UNCHANGED | Integrity: |
Confidentiality: NONE | Availability: |
Integrity: HIGH | |
Availability: NONE | |
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