Vulnerability Description
In tinyMQTT commit 6226ade15bd4f97be2d196352e64dd10937c1962 (2024-02-18), the broker mishandles protocol violations during CONNECT packet parsing. When receiving a CONNECT packet with a zero-length Client ID while CleanSession is set to 0, the broker correctly replies with a CONNACK return code 0x02 (Identifier Rejected) but fails to explicitly close the TCP connection. Since the surrounding connection teardown logic is not guaranteed to execute, each such invalid CONNECT attempt leaves the underlying socket open. Repeated attempts cause server-side resource exhaustion due to accumulating file descriptors and memory usage, potentially resulting in denial of service.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/JustDoIt0910/tinyMQTT/issues/19
- https://github.com/user-attachments/files/21207896/Resource_Exhaustion_Poc.txt
FAQ
What is CVE-2025-56352?
CVE-2025-56352 is a vulnerability with a CVSS score of 7.5 (HIGH). In tinyMQTT commit 6226ade15bd4f97be2d196352e64dd10937c1962 (2024-02-18), the broker mishandles protocol violations during CONNECT packet parsing. When receiving a CONNECT packet with a zero-length Cl...
How severe is CVE-2025-56352?
CVE-2025-56352 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-56352?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.