Memory leak in Eclipse Mosquitto
Priority LOW 31CWE-401Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-401.
Summary
In Eclipse Mosquitto version 1.6 to 2.0.10, if an authenticated client that had connected with MQTT v5 sent a crafted CONNECT message to the broker a memory leak would occur, which could be used to provide a DoS attack against the broker.
Why it matters now
EPSS 0.01113 66th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Eclipse Foundation | Eclipse Mosquitto | 1.6 and later; up to 2.0.10 | — | No fix listed | CNA |
- Eclipse Mosquitto VendorEclipse Foundation Affected 1.6 and later; up to 2.0.10 Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:* | 1.6 – 2.0.10 | Vulnerable | Eclipse Foundation |
- cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:* Versions 1.6 – 2.0.10 Vulnerable ·Eclipse Foundation
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-34431
- 2026-10-03 Alias added: GHSA-j546-3m5x-fx7p
References
More Eclipse Foundation Mosquitto vulnerabilities
- TI-2024-09749 Eclipse Mosquito: Heap Buffer Overflow in my_subscribe_callback CVSS 4.0HIGH 7.2
- TI-2018-09002 Reachable assertion in Eclipse Mosquitto CVSS 3.0HIGH 7.5
- TI-2023-12912 The broker in Eclipse Mosquitto 1.3.2 through 2.x before 2.0.16 has a memory leak that… CVSS 3.1HIGH 7.5
- TI-2017-05287 Uncontrolled resource consumption in Eclipse Mosquitto CVSS 3.0HIGH 7.5
- TI-2023-05183 Unconditionally adding an event to the epoll causes excessive CPU consumption CVSS 3.1HIGH 7.5
- TI-2018-09010 Improper authentication in Eclipse Mosquitto CVSS 3.0HIGH 8.1
Sources
- CVE-2021-34431 · CVE Program
- CVE-2021-34431 · NVD
- FIRST EPSS
- GHSA-j546-3m5x-fx7p · GitHub Advisory Database · CC BY 4.0
- CVE-2021-34431 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences