Out-of-bounds read in NanoMQ - CVE-2026-25627
Published: April 24, 2026
Vulnerability identifier: #VU127589
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-25627
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to out-of-bounds read in ws_msg_adaptor() in nng/src/sp/transport/mqttws/nmq_websocket.c when processing MQTT packets over the WebSocket listener. A remote user can send a specially crafted MQTT packet with a large Remaining Length and a shorter actual payload to cause a denial of service.
Triggering the issue requires sending a malformed PUBLISH message after a valid CONNECT over the MQTT-over-WebSocket transport.
Affected software
NanoMQ
How to mitigate CVE-2026-25627
Install security update from vendor's website.
NanoMQ - update to 0.24.1