Critical severity · published Jun 16, 2021
CVE-2021-34813
Matrix libolm before 3.2.3 allows a malicious Matrix homeserver to crash a client (while it is attempting to retrieve an Olm encrypted room key backup from the homeserver) because…
9.8
CVSS
4.3%
EPSS
No
On KEV
Description
Matrix libolm before 3.2.3 allows a malicious Matrix homeserver to crash a client (while it is attempting to retrieve an Olm encrypted room key backup from the homeserver) because olm_pk_decrypt has a stack-based buffer overflow. Remote code execution might be possible for some nonstandard build configurations.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)4.3% · higher than 91% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OL
Olm · Matrix
before 3.2.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-34813
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-34813
Patch
https://gitlab.matrix.org/matrix-org/olm/-/commit/ccc0d122ee1b4d5e5ca4ec1432086be17d5f901b
Release Notes
https://gitlab.matrix.org/matrix-org/olm/-/releases/3.2.3
Exploit
https://matrix.org/blog/2021/06/14/adventures-in-fuzzing-libolm
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