CVE-2023-28366

The broker in Eclipse Mosquitto 1.3.2 through 2.x before 2.0.16 has a memory leak that can be abused remotely when a client sends many QoS 2 messages with duplicate message IDs, and fails to respond to PUBREC commands. This occurs because of mishandling of EAGAIN from the libc send function.

Published: 2023-09-01 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-28366 is rated Moderate Risk (52.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.11%). EPSS rose +1.03% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2023-28366

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 0.08% 1.11% +1.03%
2 2025-11-21 0.69% 0.08% -0.60%
3 2025-11-18 — 0.69% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-28366

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-28366

OS Trackers for CVE-2023-28366

vendor priority summary link
alpine — CVE-2023-28366: 1 source package rows (mosquitto); 59 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 6, open 53. https://security.alpinelinux.org/vuln/CVE-2023-28366
debian not yet assigned CVE-2023-28366 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-2023-28366
gentoo low CVE-2023-28366: 1 GLSA(s) (202401-09), 1 atom(s) (app-misc/mosquitto); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-28366
redhat medium — https://access.redhat.com/security/cve/CVE-2023-28366
ubuntu medium CVE-2023-28366 medium priority: Ubuntu including 1 source packages (mosquitto), 8 status rows across 8 suites (bionic, focal, jammy, lunar, mantic, trusty, upstream, xenial): ignored 3, released 3, not-affected 2. https://ubuntu.com/security/CVE-2023-28366

Affected software / configurations for CVE-2023-28366

Vendor Product Version Raw CPE
eclipse mosquitto >= 1.3.2, < 2.0.16 cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*

References for CVE-2023-28366

cvelogic Threat Intelligence