In Eclipse Paho Go MQTT v3.1 library (paho.mqtt.golang) versions <=1.5.0 UTF-8 encoded strings, passed into the library, may be incorrectly encoded if their length exceeds 65535 bytes. This may lead to unexpected content in packets sent to the server (for example, part of an MQTT topic may leak into the message body in a PUBLISH packet). The issue arises because the length of the data passed in was converted from an int64/int32 (depending upon CPU) to an int16 without checks for overflows. The int16 length was then written, followed by the data (e.g. topic). This meant that when the data (e.g. topic) was over 65535 bytes then the amount of data written exceeds what the length field indicates. This could lead to a corrupt packet, or mean that the excess data leaks into another field (e.g. topic leaks into message body).
History

Thu, 04 Dec 2025 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Eclipse
Eclipse paho Go Mqtt
Vendors & Products Eclipse
Eclipse paho Go Mqtt

Tue, 02 Dec 2025 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 02 Dec 2025 08:30:00 +0000

Type Values Removed Values Added
Description In Eclipse Paho Go MQTT v3.1 library (paho.mqtt.golang) versions <=1.5.0 UTF-8 encoded strings, passed into the library, may be incorrectly encoded if their length exceeds 65535 bytes. This may lead to unexpected content in packets sent to the server (for example, part of an MQTT topic may leak into the message body in a PUBLISH packet). The issue arises because the length of the data passed in was converted from an int64/int32 (depending upon CPU) to an int16 without checks for overflows. The int16 length was then written, followed by the data (e.g. topic). This meant that when the data (e.g. topic) was over 65535 bytes then the amount of data written exceeds what the length field indicates. This could lead to a corrupt packet, or mean that the excess data leaks into another field (e.g. topic leaks into message body).
Weaknesses CWE-197
CWE-681
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: eclipse

Published: 2025-12-02T08:18:16.724Z

Updated: 2025-12-02T13:55:51.665Z

Reserved: 2025-09-16T07:59:33.051Z

Link: CVE-2025-10543

cve-icon Vulnrichment

Updated: 2025-12-02T13:55:44.730Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-02T09:15:46.127

Modified: 2025-12-02T17:16:29.163

Link: CVE-2025-10543

cve-icon Redhat

No data.