Cesanta Mongoose MQTT Broker main.c fn stack-based overflow
Published Sep 28, 2026
6.9
MEDIUMCVSS 4.0
EPSS 0.46%
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.
Affected products
-
- Version 7.0StatusaffectedConstraints-
- Version 7.1StatusaffectedConstraints-
- Version 7.10StatusaffectedConstraints-
- Version 7.11StatusaffectedConstraints-
- Version 7.12StatusaffectedConstraints-
- Version 7.13StatusaffectedConstraints-
- Version 7.14StatusaffectedConstraints-
- Version 7.15StatusaffectedConstraints-
- Version 7.16StatusaffectedConstraints-
- Version 7.17StatusaffectedConstraints-
- Version 7.18StatusaffectedConstraints-
- Version 7.19StatusaffectedConstraints-
- Version 7.2StatusaffectedConstraints-
- Version 7.20StatusaffectedConstraints-
- Version 7.21StatusaffectedConstraints-
- Version 7.3StatusaffectedConstraints-
- Version 7.4StatusaffectedConstraints-
- Version 7.5StatusaffectedConstraints-
- Version 7.6StatusaffectedConstraints-
- Version 7.7StatusaffectedConstraints-
- Version 7.8StatusaffectedConstraints-
- Version 7.9StatusaffectedConstraints-
- Version 7.22StatusunaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cesanta | Mongoose | n/a |
|
No data.
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
Red Hat statement
This vulnerability is evaluated as having Moderate impact for Red Hat because, although triggered remotely over network inputs without authentication, the scope of impact is limited to a denial of service crash and targets demonstration code rather than core platform functionality. The flawed broker logic resides within upstream tutorial files that are not deployed or enabled in supported Red Hat products. Any potential risk is confined to specialized community builds where this standalone server example is explicitly compiled and exposed to untrusted traffic.
Metrics
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
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
1 other source (CVE.org) ▾
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
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
AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed Oct 1, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.46% (0.00462) | 37.86th | v5 (v2026.06.15) |
| Oct 1, 2026 | 0.46% (0.00462) | 37.74th | v5 (v2026.06.15) |
References (11)
- https://access.redhat.com/security/cve/CVE-2026-101003 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2542308 Issue Tracking
- https://github.com/cesanta/mongoose/ product
- https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71 patch
- https://github.com/cesanta/mongoose/releases/tag/7.22 patch
- https://nvd.nist.gov/vuln/detail/CVE-2026-101003
- https://vuldb.com/cve/CVE-2026-101003 third-party-advisory
- https://vuldb.com/submit/920005 third-party-advisory
- https://vuldb.com/vuln/410873 vdb-entrytechnical-description
- https://vuldb.com/vuln/410873/cti signaturepermissions-required
- https://www.cve.org/CVERecord?id=CVE-2026-101003
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2026-101003 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2542308 | Issue Tracking | |
| https://github.com/cesanta/mongoose/ | product | |
| https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71 | patch | |
| https://github.com/cesanta/mongoose/releases/tag/7.22 | patch | |
| https://nvd.nist.gov/vuln/detail/CVE-2026-101003 | ||
| https://vuldb.com/cve/CVE-2026-101003 | third-party-advisory | |
| https://vuldb.com/submit/920005 | third-party-advisory | |
| https://vuldb.com/vuln/410873 | vdb-entrytechnical-description | |
| https://vuldb.com/vuln/410873/cti | signaturepermissions-required | |
| https://www.cve.org/CVERecord?id=CVE-2026-101003 |
Change history (0)
No recorded changes yet.