CVE-2021-45936

Name: CVE-2021-45936
Creator: NVD / NIST
Published: 2022-01-01T01:15:08.73+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.89%

Last modified Jun 17, 2026

CVE-2021-45936 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttDecode_Disconnect (called from MqttClient_DecodePacket and MqttClient_WaitType).. EPSS estimates a 0.89% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability

0.89%

54.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Wolfssl	Wolfmqtt	1.9

References

https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=39053Exploit, Issue Tracking, Third Party Advisory
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/wolfmqtt/OSV-2021-1348.yamlExploit, Third Party Advisory
https://github.com/wolfSSL/wolfMQTT/commit/84d4b53122e0fa0280c7872350b89d5777dabbb2Patch, Third Party Advisory
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=39053Exploit, Issue Tracking, Third Party Advisory
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/wolfmqtt/OSV-2021-1348.yamlExploit, Third Party Advisory
https://github.com/wolfSSL/wolfMQTT/commit/84d4b53122e0fa0280c7872350b89d5777dabbb2Patch, Third Party Advisory

Timeline

Published: Jan 1, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-45936?

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

How severe is CVE-2021-45936?

CVE-2021-45936 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.89% probability of exploitation in the next 30 days.

How do I fix CVE-2021-45936?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-45936?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST