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TI-2021-20941 Aliases CVE-2021-45937GHSA-c4q4-j5v5-qp8x

wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called…

Priority LOW 27CWE-787Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Connect).

Why it matters now

EPSS 0.00917 60th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:wolfssl:wolfmqtt:1.9:*:*:*:*:*:*:*1.9VulnerablewolfSSL
  • cpe:2.3:a:wolfssl:wolfmqtt:1.9:*:*:*:*:*:*:* Versions 1.9 Vulnerable ·wolfSSL

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-45937
  2. 2026-10-03 Alias added: GHSA-c4q4-j5v5-qp8x

References

Exploit 2

Patch 1

  • TI-2021-20943 wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called… CVSS 3.1MEDIUM 5.5
  • TI-2021-20942 wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called… CVSS 3.1MEDIUM 5.5
  • TI-2021-20940 wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttDecode_Disconnect (called… CVSS 3.1MEDIUM 5.5
  • TI-2021-20938 wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called… CVSS 3.1MEDIUM 5.5
  • TI-2021-20937 wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow (8 bytes) in MqttDecode_Publish… CVSS 3.1MEDIUM 5.5
  • TI-2021-20936 wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow (4 bytes) in MqttDecode_Publish… CVSS 3.1MEDIUM 5.5

Sources

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