What’s Vulnerable › Vulnerabilities

CVE-2018-12551

• Severity: high (CVSS 8.1 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-03-27 · updated 2026-06-17
• Weakness: CWE-703

Description

When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for authentication, any malformed data in the password file will be treated as valid. This typically means that the malformed data becomes a username and no password. If this occurs, clients can circumvent authentication and get access to the broker by using the malformed username. In particular, a blank line will be treated as a valid empty username. Other security measures are unaffected. Users who have only used the mosquitto_passwd utility to create and modify their password files are unaffected by this vulnerability.

Affected products

• The Eclipse Foundation Eclipse Mosquitto: from 1.0 through 1.5.5

References

• https://bugs.eclipse.org/bugs/show_bug.cgi?id=543401
• https://lists.debian.org/debian-lts-announce/2019/10/msg00035.html
• https://bugs.eclipse.org/bugs/show_bug.cgi?id=543401
• https://lists.debian.org/debian-lts-announce/2019/10/msg00035.html

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