What is CVE-2023-0809?

CVE-2023-0809 is a medium-severity vulnerability in Eclipse Mosquitto, classified under CWE-789. CVSS score: 5.8/10. Published 2023-10-02.

How severe is CVE-2023-0809?

Medium severity. CVSS v3 base score is 5.8 out of 10.

Resource exhaustion in Eclipse Mosquitto

CVE-2023-0809

In Mosquitto before 2.0.16, excessive memory is allocated based on malicious initial packets that are not CONNECT packets.

Published 2023-10-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.007 (51.6th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Eclipse Mosquitto — versions 0

Weakness classification (CWE)

References

mosquitto.org/blog/2023/08/version-2-0-16-released/ (Release Notes)
security.gentoo.org/glsa/202401-09

Frequently asked questions

What is CVE-2023-0809?: CVE-2023-0809 is a medium-severity vulnerability in Eclipse Mosquitto, classified under CWE-789. CVSS score: 5.8/10. Published 2023-10-02.
How severe is CVE-2023-0809?: Medium severity. CVSS v3 base score is 5.8 out of 10.