Cesanta Mongoose up to 7.21 MQTT Broker main.c fn stack-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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4.8$0-$5k1.72+

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Cesanta Mongoose up to 7.21. Affected by this issue is the function fn of the file tutorials/mqtt/mqtt-server/main.c of the component MQTT Broker. The manipulation leads to stack-based overflow. This vulnerability is listed as CVE-2026-101003. The attack may be initiated remotely. In addition, an exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Cesanta Mongoose up to 7.21 and classified as problematic. This issue affects the function fn of the file tutorials/mqtt/mqtt-server/main.c of the component MQTT Broker. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is availability.

The identification of this vulnerability is CVE-2026-101003. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details as well as a public exploit are known.

It is declared as proof-of-concept.

Upgrading to version 7.22 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch a9df523f76f43a38bd53b4232b9cfd4c16869e71 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 4.8

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mongoose 7.22
Patch: a9df523f76f43a38bd53b4232b9cfd4c16869e71

Timelineinfo

09/27/2026 Advisory disclosed
09/27/2026 +0 days VulDB entry created
09/27/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Status: Confirmed

CVE: CVE-2026-101003 (🔒)
GCVE (CVE): GCVE-0-2026-101003
GCVE (VulDB): GCVE-100-410873
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 09/27/2026 12:34
Changes: 09/27/2026 12:34 (58)
Complete: 🔍
Submitter: nemo2533
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #920005: Cesanta Mongoose 7.20 Stack Buffer Overflow (by nemo2533)

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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