A vulnerability classified as critical has been found in matrix-js-sdk up to 19.6.x. This affects an unknown code of the component Verification Handler. The manipulation with an unknown input leads to a key exchange without entity authentication vulnerability. CWE is classifying the issue as CWE-322. The product performs a key exchange with an actor without verifying the identity of that actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Matrix JavaScript SDK is the Matrix Client-Server software development kit (SDK) for JavaScript. Prior to version 19.7.0, an attacker cooperating with a malicious homeserver could interfere with the verification flow between two users, injecting its own cross-signing user identity in place of one of the users’ identities. This would lead to the other device trusting/verifying the user identity under the control of the homeserver instead of the intended one. The vulnerability is a bug in the matrix-js-sdk, caused by checking and signing user identities and devices in two separate steps, and inadequately fixing the keys to be signed between those steps. Even though the attack is partly made possible due to the design decision of treating cross-signing user identities as Matrix devices on the server side (with their device ID set to the public part of the user identity key), no other examined implementations were vulnerable. Starting with version 19.7.0, the matrix-js-sdk has been modified to double check that the key signed is the one that was verified instead of just referencing the key by ID. An additional check has been made to report an error when one of the device ID matches a cross-signing key. As this attack requires coordination between a malicious homeserver and an attacker, those who trust their homeservers do not need a particular workaround.

The weakness was released 09/29/2022 as GHSA-5w8r-8pgj-5jmf. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2022-39250 since 09/02/2022. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 19.7.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch a587d7c36026fe1fcf93dfff63588abee359be76 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Productinfo

Name

• matrix-js-sdk

Version

• 19.0
• 19.1
• 19.2
• 19.3
• 19.4
• 19.5
• 19.6

License

• open-source

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CPE 2.2info

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