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No exploitation reportedFix available

CVE-2018-12551

No exploitation reported by the sources we read.

  • Published2019-03-27
  • WeaknessCWE-287 · CWE-703

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2019-03-2718:29CVE publishedNVD

Versions per branch

NVD
Eclipse mosquitto
BranchAffectedFixed in
1.x≥ 1.0, ≤ 1.5.5no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • mosquittoUbuntu:18.04:LTSall versions · fixed in 1.4.15-2ubuntu0.18.04.1
  • mosquittoUbuntu:16.04:LTSall versions · fixed in 1.4.8-1ubuntu0.16.04.5
  • mosquittoSUSE:Package Hub 15all versions · fixed in 1.4.15-bp150.3.3.1
  • mosquittoDebian:14all versions · fixed in 1.5.6-1
  • mosquittoDebian:13all versions · fixed in 1.5.6-1
  • mosquittoDebian:12all versions · fixed in 1.5.6-1
  • mosquittoDebian:9all versions · fixed in 1.4.10-3+deb9u3
  • mosquittoDebian:8all versions · fixed in 1.3.4-2+deb8u4

19 more package ranges on OSV.dev

Vendor advisories

  • CVE-2018-12551 Red Hat Product Security

    mosquitto: improper authentication in password file

Full record on NVD

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.08.1read 2026-10-23
  • NVDCVSS 2.06.8read 2026-10-23
  • CNAweakness (CWE)CWE-703known since 2026-10-23
  • NVDweakness (CWE)CWE-287read 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-11-09
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2019-03-27
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-5hh6-jrm5-mqxq

Frequently asked questions

What is CVE-2018-12551?

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.

Is CVE-2018-12551 actively exploited?

Active exploitation of CVE-2018-12551 has not been confirmed. Its EPSS score was 1.5% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-12551?

CVE-2018-12551 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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