Buffer overflow in Matrix Olm

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 olm_pk_decrypt has a stack-based buffer overflow. Remote co…

Vulnerability class: Buffer Overflow

EPSS: 0.043 (90.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-34813?
CVE-2021-34813 is a critical-severity vulnerability in Matrix Olm, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2021-06-16.
How severe is CVE-2021-34813?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-34813 known to be exploited?
5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.