Medium severity · published Sep 13, 2021
CVE-2021-40824
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…
5.9
CVSS
0.7%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 51% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EL
Element · Matrix
before 1.2.2 · source: NVD
MA
Matrix-android-sdk2 · Matrix
before 1.2.2 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-40824
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-40824
Patch
https://github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.2.2
Vendor Advisory
https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing
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