Resource exhaustion in Zeromq Libzmq

CVE-2020-15166

In ZeroMQ before version 4.3.3, there is a denial-of-service vulnerability. Users with TCP transport public endpoints, even with CURVE/ZAP enabled, are impacted. If a raw TCP socket is opened and connected to an endpoint that is fully configured with CURVE/ZAP, legitimate clients will not be able to exchange any message. Handshakes complete successfully, and messages are delivered to the library, but the server application never receives them. This is patched in version 4.3.3.

Vulnerability class: DoS (Denial of Service)

EPSS: 0.034 (87.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2020-15166?
CVE-2020-15166 is a high-severity vulnerability in Zeromq Libzmq, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2020-09-11.
How severe is CVE-2020-15166?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2020-15166 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.