CVE-2026-25627 MEDIUM

CVE-2026-25627: nanomq: OOB Read / Crash (DoS) via Malformed MQTT Remaining Length over WebSocket

Vendor Nanomq
Product nanomq
Weakness CWE-125
Published March 30, 2026
Last update March 31, 2026

CVSS base score

6.5/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. Prior to version 0.24.8, NanoMQ’s MQTT-over-WebSocket transport can be crashed by sending an MQTT packet with a deliberately large Remaining Length in the fixed header while providing a much shorter actual payload. The code path copies Remaining Length bytes without verifying that the current receive buffer contains that many bytes, resulting in an out-of-bounds read (ASAN reports OOB / crash). This is remotely triggerable over the WebSocket listener. This issue has been patched in version 0.24.8.

Key dates

02Disclosure timeline

March 30, 2026 CVE published
March 31, 2026 Record updated