CVE-2021-40824

Description

A logic error in the room key sharing functionality of Element Android before 1.2.2 and matrix-android-sdk2 (aka Matrix SDK for Android) before 1.2.2 allows a malicious Matrix homeserver present in an encrypted room to steal room encryption keys (via crafted Matrix protocol messages) that were originally sent by affected Matrix clients participating in that room. This allows the attacker to decrypt end-to-end encrypted messages sent by affected clients.

Category

5.9
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.24%
Vendor Advisory matrix.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing vendor advisory
https://github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.2.2 third party advisory patch

Frequently Asked Questions

What is the severity of CVE-2021-40824?
CVE-2021-40824 has been scored as a medium severity vulnerability.
How to fix CVE-2021-40824?
To fix CVE-2021-40824, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-40824 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-40824 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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