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TI-2020-11938 Aliases CVE-2020-15166

Denial of Service in ZeroMQ

Priority LOW 39CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-400.

Summary

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.

Why it matters now

EPSS 0.03316 88th percentileScored 2026-11-07
Fix Partial libzmq (zeromq): 4.3.3Red Hat: 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
zeromqlibzmqbefore 4.3.34.3.3Patch availableCNA
  • libzmq Vendorzeromq Affected before 4.3.3 Fixed in 4.3.3 Patch available CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:a:zeromq:libzmq:*:*:*:*:*:*:*:*before 4.3.3Vulnerablezeromq
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*32VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
  • cpe:2.3:a:zeromq:libzmq:*:*:*:*:*:*:*:* Versions before 4.3.3 Vulnerable ·zeromq
  • cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian

Remediation

  • Fix · CNA libzmq (zeromq) Fixed in 4.3.3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Ceph Storage 2AffectedNo fix planned: Out of support scope

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-15166

References

Patch 3

Advisory 4

  • TI-2019-09836 In ZeroMQ libzmq before 4.0.9, 4.1.x before 4.1.7, and 4.2.x before 4.3.2, a remote… CVSS 3.1CRITICAL 9.8
  • TI-2021-03530 Buffer overflow in zeromq CVSS 3.1HIGH 8.1
  • TI-2019-04448 A pointer overflow, with code execution, was discovered in ZeroMQ libzmq (aka 0MQ) 4.2.x… CVSS 3.0HIGH 8.8
  • TI-2020-18651 ZeroMQ libzmq 4.3.3 has a heap-based buffer overflow in zmq::tcp_read, a different vulnerability than CVE-2021-20235. CVSS 3.1CRITICAL 9.8
  • TI-2021-03532 Uncontrolled resource consumption in zeromq CVSS 3.1HIGH 7.5
  • TI-2021-03529 Uncontrolled resource consumption in zeromq CVSS 3.1MEDIUM 6.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences