CVE-2021-45939
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from...
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Subscribe).
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Subscribe).
- Record
CVE-2021-45939- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:N/A:P - Weakness
- CWE-787
- Updated
- 2026-11-02
CVE List No score
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Subscribe).
- Record
CVE-2021-45939- Updated
- 2026-11-02
EUVDEUVD-2021-32648 No score
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Subscribe).
- Record
EUVD-2021-32648- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-jc37-rmrx-qcxg No score
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from...
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Subscribe).
- Record
GHSA-jc37-rmrx-qcxg- Weakness
- CWE-787
- Updated
- 2026-11-02
OSV
wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Subscribe).
- Record
CVE-2021-45939- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-45939 is a medium vulnerability (CVSS 5.5) in Wolfssl Wolfmqtt, published December 31, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.92%, the 60th percentile. No source names a fixed version.