CVE-2018-12551

Exp

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.

Published: 2019-03-27 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-12551 is rated High Exploit Risk (72.9/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.47%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2018-12551

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2018-12551

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.60% 1.47% +0.88%
2 2026-05-27 0.71% 0.60% -0.11%
3 2025-11-21 — 0.71% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-12551

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.0 HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2018-12551

OS Trackers for CVE-2018-12551

vendor priority summary link
alpine high CVE-2018-12551: 1 source package rows (mosquitto); 30 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 20. https://security.alpinelinux.org/vuln/CVE-2018-12551
debian not yet assigned CVE-2018-12551 not yet assigned priority: Debian including 1 source packages (mosquitto), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-12551
ubuntu medium CVE-2018-12551 medium priority: Ubuntu including 1 source packages (mosquitto), 6 status rows across 6 suites (bionic, cosmic, disco, trusty, upstream, xenial): released 4, not-affected 2. https://ubuntu.com/security/CVE-2018-12551

Affected software / configurations for CVE-2018-12551

Vendor Product Version Raw CPE
eclipse mosquitto >= 1.0, <= 1.5.5 cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*

References for CVE-2018-12551

cvelogic Threat Intelligence