CVE-2026-101003 Cesanta Mongoose MQTT Broker main.c fn stack-based overflow
A stack-based buffer overflow in the Cesanta Mongoose MQTT Broker allows remote attackers to execute arbitrary code or cause denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-101003?
CVE-2026-101003 is a medium-severity memory corruption vulnerability in Cesanta Mongoose, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A weakness has been identified in Cesanta Mongoose up to 7.21. Affected by this vulnerability is the function fn of the file tutorials/mqtt/mqtt-server/main.c of the component MQTT Broker. Executing a manipulation can lead to stack-based buffer overflow. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 7.22 addresses this issue. This patch is called a9df523f76f43a38bd53b4232b9cfd4c16869e71. Upgrading the affected component is advised.
Which versions are affected by CVE-2026-101003?
How do I fix CVE-2026-101003?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-101003 being exploited?
There is no known exploitation of CVE-2026-101003 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-101003, GHSA-g7gm-388f-77vf, UBUNTU-CVE-2026-101003.