Vulnerability record · CVE-2025-56353 · published 20 January 2026
CVE-2025-56353: Justdoit0910 tinymqtt memory leak vulnerability
JJustdoit0910 · Tinymqtt
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.
Description
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://github.com/JustDoIt0910/tinyMQTT/issues/19 | ExploitIssue TrackingThird Party Advisory |
Track CVE-2025-56353 inside VULONE
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2025-56353), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.
