CVE-2018-12551
HIGHEPSS 71th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Elevated risk: more likely to be exploited than 71% of all known CVEs.
References
Related Vulnerabilities
Other CWE-703 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-21894 | Critical | 9.8 | 19% | - | - |
| CVE-2025-59538 | High | 7.5 | 8.3% | - | Fix |
| CVE-2019-5031 | High | 8.8 | 6.0% | - | - |
| CVE-2023-49786 | High | 7.5 | 5.3% | - | Fix |
| CVE-2024-10781 | High | 8.1 | 3.8% | - | Fix |
| CVE-2024-22052 | High | 7.5 | 3.8% | - | - |
Common questions
How do I fix CVE-2018-12551?
Upgrade mosquitto on debian 11 to 1.5.6-1 or later.
Is CVE-2018-12551 being actively exploited?
Not that we know of. CVE-2018-12551 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.5% is the estimated probability that it will be exploited in the next 30 days. That is higher than 71% of all scored CVEs.
How severe is CVE-2018-12551?
CVE-2018-12551 has a CVSS v3 base score of 8.1, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2018-12551 affect?
Published advisories record a fix for mosquitto (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.