Vulnerability in Justdoit0910 Tinymqtt
CVE-2025-56353
In tinyMQTT commit 6226ade15bd4f97be2d196352e64dd10937c1962 (2024-02-18), a memory leak occurs due to the broker's failure to validate or reject malformed UTF-8 strings in topic filters. An attacker can exploit this by sending repeated subscription requests with arbitrarily large or invalid filter payloads. Each request causes memory to be allocated for the malformed topic filter, but the broker does not free the associated memory, leading to unbounded heap growth and potential denial of service under sustained attack.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (23.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Justdoit0910 Tinymqtt — versions 2024-02-18
Weakness classification (CWE)
References
- github.com/JustDoIt0910/tinyMQTT/issues/19 (Exploit, Third Party Advisory, Issue Tracking)
Frequently asked questions
- What is CVE-2025-56353?
- CVE-2025-56353 is a high-severity vulnerability in Justdoit0910 Tinymqtt, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 7.5/10. Published 2026-01-20.
- How severe is CVE-2025-56353?
- High severity. CVSS v3 base score is 7.5 out of 10.