VULNERABILITY INTELLIGENCE

CVE-2025-56353

CVSS score7.5 HIGH
EPSS probability0.33%
CISA KEVNot currently listed
Published2026-01-20
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Weakness classification

  • 134c704f-9b21-4f2e-91b3-4a467353bcc0: CWE-401

Primary references