Vulnerability Details CVE-2022-39249
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 33.2%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2022-39249
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cpe:2.3:a:matrix:javascript_sdk:17.1.0
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cpe:2.3:a:matrix:javascript_sdk:17.2.0
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cpe:2.3:a:matrix:javascript_sdk:18.0.0
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cpe:2.3:a:matrix:javascript_sdk:18.1.0
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cpe:2.3:a:matrix:javascript_sdk:19.0.0
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cpe:2.3:a:matrix:javascript_sdk:19.1.0
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cpe:2.3:a:matrix:javascript_sdk:19.2.0
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cpe:2.3:a:matrix:javascript_sdk:19.3.0
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cpe:2.3:a:matrix:javascript_sdk:19.4.0
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cpe:2.3:a:matrix:javascript_sdk:19.5.0
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cpe:2.3:a:matrix:javascript_sdk:19.6.0