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Vulnerabilities

Vulnerability · CVE-2025-10543

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 exc…

Published Dec 2, 2025 · catalog updated Oct 18, 2026 · paho mqtt

Check if you run it

No confirmed exploitation is on record for CVE-2025-10543. EPSS is 0.23%. Act only if a listed version of paho mqtt is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.23%
Remediation
Version ranges on file
Affected products
cpe eclipse/paho mqtt · stated paho mqtt

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).

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe eclipse/paho mqttversion unspecified
  • stated paho mqtt<= 1.5.0

How to fix CVE-2025-10543

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-10543. EPSS is 0.23%. Act only if a listed version of paho mqtt is installed.

Which versions are affected?

Compare what you have installed with paho mqtt <= 1.5.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-197; CWE-681. EPSS 0.23%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 2, 2025 · NIST NVD

    Detected

    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 wa

  2. Oct 18, 2026 · NIST NVD

    Updated

    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 wa

Sources

  • CVE.orgVulnerability recordCVE-2025-10543

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-10543

    30-day exploitation probability 0.23%

    first.org
  • NIST NVDVulnerability recordCVE-2025-10543

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 21, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.