Medium severity · published Sep 28, 2026
CVE-2026-101003
Cesanta Mongoose MQTT Broker main.c fn stack-based overflow
5.3
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 40% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
Mongoose · Cesanta
7.0; 7.1; 7.2; 7.3; 7.4; 7.5; +16 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-101003
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-101003
vdb-entry
https://vuldb.com/vuln/410873
signature
https://vuldb.com/vuln/410873/cti
third-party-advisory
https://vuldb.com/cve/CVE-2026-101003
third-party-advisory
https://vuldb.com/submit/920005
patch
https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71
patch
https://github.com/cesanta/mongoose/releases/tag/7.22
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