Vulnerability Details CVE-2022-39251
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 that legitimately appear to have come from another person, without any indication such as a grey shield. Additionally, a sophisticated attacker cooperating with a malicious homeserver could employ this vulnerability to perform a targeted attack in order to send fake to-device messages appearing to originate from another user. This can allow, for example, to inject the key backup secret during a self-verification, to make a targeted device start using a malicious key backup spoofed by the homeserver. These attacks are possible due to a protocol confusion vulnerability that accepts to-device messages encrypted with Megolm instead of Olm. Starting with version 19.7.0, matrix-js-sdk has been modified to only accept Olm-encrypted to-device messages. Out of caution, several other checks have been audited or added. This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 34.3%
CVSS Severity
CVSS v3 Score 8.6
Products affected by CVE-2022-39251
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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