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Fencer Vulns
high 8.1

CVE-2018-12551 json

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…

published 2019-03-27 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-4511

cvss
8.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

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.

Patch / fix

  • mosquitto Debian 14, Debian 13, Debian 12 1.5.6-1

debian advisories DEBIAN-CVE-2018-12551

  • mosquitto Ubuntu 16.04 LTS 1.4.8-1ubuntu0.16.04.5
  • mosquitto Ubuntu 18.04 LTS 1.4.15-2ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2018-12551

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • mosquitto Package Hub 15 1.4.15-bp150.3.3.1

opensuse advisories openSUSE-SU-2019:0237-1

  • mosquitto Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 1.5.6-r0
  • mosquitto Alpine 3.7 1.4.15-r1
  • mosquitto Alpine 3.8 1.4.15-r4

alpine advisories ALPINE-CVE-2018-12551

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-12551 updated cvss 7.1

mosquitto: improper authentication in password file

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.47% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugs.eclipse.org https://bugs.eclipse.org/bugs/show_bug.cgi?id=543401 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 8.1 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • The Eclipse Foundation Eclipse Mosquitto

Classification

Weakness
  • CWE-703 Improper Check or Handling of Exceptional Conditions
  • CWE-287 Improper Authentication

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.