# CVE-2021-41039: mosquitto: In versions 1.6 to 2.0.11 of Eclipse Mosquitto, an MQTT v5 client connecting with a large number of user-property pro...

CVE-2021-41039 is fixed in 4 products on 1 platform, first by DEBIAN-CVE-2021-41039, released December 1, 2021. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-41039
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0136
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 1, 2021

## Description

In versions 1.6 to 2.0.11 of Eclipse Mosquitto, an MQTT v5 client connecting with a large number of user-property properties could cause excessive CPU usage, leading to a loss of performance and possible denial of service.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libmosquitto1 Ubuntu 20.04 LTS (focal) | 1.6.9-1ubuntu0.1~esm1 | [libmosquitto1 1.6.9-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libmosquitto1-1.6.9-1ubuntu0.1-esm1.md) | Oct 2, 2023 |
| Linux | libmosquitto1 Ubuntu 22.04.1 LTS (jammy) | 2.0.11-1ubuntu1.1 | [libmosquitto1 2.0.11-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libmosquitto1-2.0.11-1ubuntu1.1.md) | Oct 2, 2023 |
| Linux | libmosquittopp1 Ubuntu 20.04 LTS (focal) | 1.6.9-1ubuntu0.1~esm1 | [libmosquittopp1 1.6.9-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libmosquittopp1-1.6.9-1ubuntu0.1-esm1.md) | Oct 2, 2023 |
| Linux | libmosquittopp1 Ubuntu 22.04.1 LTS (jammy) | 2.0.11-1ubuntu1.1 | [libmosquittopp1 2.0.11-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libmosquittopp1-2.0.11-1ubuntu1.1.md) | Oct 2, 2023 |
| Linux | mosquitto Debian 12.15 (bookworm) | 2.0.11-1.2 | [DEBIAN-CVE-2021-41039](https://patchblox.com/security/data/fix/linux/debian-cve-2021-41039.md) | Dec 1, 2021 |
| Linux | mosquitto Debian 13.5 (trixie) | 2.0.11-1.2 | [DEBIAN-CVE-2021-41039](https://patchblox.com/security/data/fix/linux/debian-cve-2021-41039.md) | Dec 1, 2021 |
| Linux | mosquitto Debian 14 | 2.0.11-1.2 | [DEBIAN-CVE-2021-41039](https://patchblox.com/security/data/fix/linux/debian-cve-2021-41039.md) | Dec 1, 2021 |
| Linux | mosquitto Ubuntu 20.04 LTS (focal) | 1.6.9-1ubuntu0.1~esm1 | [mosquitto 1.6.9-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-mosquitto-1.6.9-1ubuntu0.1-esm1.md) | Oct 2, 2023 |
| Linux | mosquitto Ubuntu 22.04.1 LTS (jammy) | 2.0.11-1ubuntu1.1 | [mosquitto 2.0.11-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-mosquitto-2.0.11-1ubuntu1.1.md) | Oct 2, 2023 |
| Linux | mosquitto-clients Ubuntu 20.04 LTS (focal) | 1.6.9-1ubuntu0.1~esm1 | [mosquitto-clients 1.6.9-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-mosquitto-clients-1.6.9-1ubuntu0.1-esm1.md) | Oct 2, 2023 |
| Linux | mosquitto-clients Ubuntu 22.04.1 LTS (jammy) | 2.0.11-1ubuntu1.1 | [mosquitto-clients 2.0.11-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-mosquitto-clients-2.0.11-1ubuntu1.1.md) | Oct 2, 2023 |

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Data as of 2026-11-10T01:44:33Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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