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CVE-2018-12551

When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for...

8.1 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

1.47%Up 0.9 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 8.1

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.

Record
CVE-2018-12551
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness
CWE-703, CWE-287
Updated
2026-11-02
CVE List No score

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.

Record
CVE-2018-12551
Weakness
CWE-703
Updated
2026-11-02
EUVDEUVD-2018-4511 No score

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.

Record
EUVD-2018-4511
Updated
2026-11-03
GitHub AdvisoriesGHSA-5hh6-jrm5-mqxq 8.1

When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for...

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.

Record
GHSA-5hh6-jrm5-mqxq
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-287
Updated
2026-11-02
OSVALPINE-CVE-2018-12551 8.1

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.

Record
ALPINE-CVE-2018-12551
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVBELL-CVE-2018-12551 8.1

CVE-2018-12551 does not affect BellSoft software

Record
BELL-CVE-2018-12551
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
Show 6 moreShow less
OSV 8.1

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.

Record
CVE-2018-12551
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2018-12551 8.1

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.

Record
DEBIAN-CVE-2018-12551
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2018-12551 8.1

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.

Record
UBUNTU-CVE-2018-12551
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVopenSUSE-SU-2019:0233-1 No score

Security update for mosquitto

This update for mosquitto fixes the following issues:

Security issues fixed:

  • CVE-2018-12546: Fixed an issue with revoked access to topics (bsc#1125019).
  • CVE-2018-12551: Fixed an issue which allowed malformed data in the password file to be treated as valid (bsc#1125020).
  • CVE-2018-12550: Fixed an an issue which treats an empty ACL file wrongly (bsc#1125021).
Record
openSUSE-SU-2019:0233-1
Updated
2026-11-02
OSVopenSUSE-SU-2019:0237-1 No score

Security update for mosquitto

This update for mosquitto fixes the following issues:

Security issues fixed:

  • CVE-2018-12546: Fixed an issue with revoked access to topics (bsc#1125019).
  • CVE-2018-12551: Fixed an issue which allowed malformed data in the password file to be treated as valid (bsc#1125020).
  • CVE-2018-12550: Fixed an an issue which treats an empty ACL file wrongly (bsc#1125021).

This update was imported from the openSUSE:Leap:15.0:Update update project.

Record
openSUSE-SU-2019:0237-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:11057-1 No score

libmosquitto1-2.0.11-1.2 on GA media

These are all security issues fixed in the libmosquitto1-2.0.11-1.2 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:11057-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
mosquitto
Alpine:v3.10
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.11
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.12
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.13
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.14
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.15
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.16
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.17
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.18
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.19
 1.0 up to 1.5.6-r0
1.5.6-r0
Show 16 moreShow less
Affected packages
PackageAffectedFixed
mosquitto
Alpine:v3.20
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.21
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.22
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.23
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.24
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Alpine:v3.7
 1.0 up to 1.4.15-r1
1.4.15-r1
mosquitto
Alpine:v3.8
 1.0 up to 1.4.15-r4
1.4.15-r4
mosquitto
Alpine:v3.9
 1.0 up to 1.5.6-r0
1.5.6-r0
mosquitto
Debian:12
 before 1.5.6-1
1.5.6-1
mosquitto
Debian:13
 before 1.5.6-1
1.5.6-1
mosquitto
Debian:14
 before 1.5.6-1
1.5.6-1
mosquitto
Debian:8
From an advisory covering 4 CVEs
 before 1.3.4-2+deb8u4, plus listed versions
1.3.4-21.3.4-2+deb8u11.3.4-2+deb8u21.3.4-2+deb8u3
1.3.4-2+deb8u4
mosquitto
Debian:9
From an advisory covering 3 CVEs
 before 1.4.10-3+deb9u3, plus listed versions
1.4.10-31.4.10-3+deb9u11.4.10-3+deb9u2
1.4.10-3+deb9u3
mosquitto
Ubuntu:16.04:LTS
 before 1.4.8-1ubuntu0.16.04.5, plus listed versions
1.4.3-11.4.4-11.4.7-11.4.8-11.4.8-1build1
Show 4 moreShow less
1.4.8-1ubuntu0.16.04.11.4.8-1ubuntu0.16.04.21.4.8-1ubuntu0.16.04.31.4.8-1ubuntu0.16.04.4
1.4.8-1ubuntu0.16.04.5
mosquitto
Ubuntu:18.04:LTS
 before 1.4.15-2ubuntu0.18.04.1, plus listed versions
1.4.12-11.4.14-11.4.14-21.4.14-2build11.4.15-11.4.15-2
1.4.15-2ubuntu0.18.04.1
mosquitto
SUSE:Package Hub 15
From an advisory covering 3 CVEs
 before 1.4.15-bp150.3.3.1
1.4.15-bp150.3.3.1

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-12551 is a high vulnerability (CVSS 8.1) in Eclipse Mosquitto, published February 10, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.47%, the 73rd percentile. Fixed in mosquitto 1.5.6-r0.

References

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