Buffer overflow in Zeromq

CVE-2021-20236

A flaw was found in the ZeroMQ server in versions before 4.3.3. This flaw allows a malicious client to cause a stack buffer overflow on the server by sending crafted topic subscription requests and then unsubscribing. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Vulnerability class: Buffer Overflow

EPSS: 0.016 (74.6th 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)

References

Frequently asked questions

What is CVE-2021-20236?
CVE-2021-20236 is a critical-severity vulnerability in Zeromq, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2021-05-28.
How severe is CVE-2021-20236?
Critical severity. CVSS v3 base score is 9.8 out of 10.