CVE-2026-101003

Cesanta Mongoose MQTT Broker main.c fn stack-based overflow

State: Published
Severity: 6.9 Medium
Published: Sep 28, 2026
Updated: Oct 1, 2026
Reserved: Sep 27, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P	VulDB
3.1	5.3 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C	VulDB
3.0	5.3 Medium	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C	VulDB
2.0	5.0 Medium	AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C	VulDB

Weaknesses

CWE-121 Stack-based Buffer Overflow
CWE-119 Memory Corruption

Affected Products

Product	Versions
MongooseCesanta	7.0Affected 7.1Affected 7.2Affected 7.3Affected 7.4Affected 7.5Affected 7.6Affected 7.7Affected 7.8Affected 7.9Affected 7.10Affected 7.11Affected 7.12Affected 7.13Affected 7.14Affected 7.15Affected 7.16Affected 7.17Affected 7.18Affected 7.19Affected 7.20Affected 7.21Affected 7.22Not affected

References

VDB-410873 | Cesanta Mongoose MQTT Broker main.c fn stack-based overflowvdb-entrytechnical-description
VDB-410873 | CTI Indicators (IOB, IOC, IOA)signaturepermissions-required
CVE-2026-101003 | CVE Analysis and Reportthird-party-advisory
Submit #920005 | Cesanta Mongoose 7.20 Stack Buffer Overflowthird-party-advisory
https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71patch
https://github.com/cesanta/mongoose/releases/tag/7.22patch
https://github.com/cesanta/mongoose/product

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