CVE-2023-0809

In Mosquitto before 2.0.16, excessive memory is allocated based on malicious initial packets that are not CONNECT packets.

Published: 2023-10-02 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-0809 is rated Low Risk (39.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.61%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2023-0809

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 0.05% 0.61% +0.56%
2 2026-02-07 0.03% 0.05% +0.02%
3 2025-11-21 — 0.03% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-0809

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L 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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]

Weakness enumeration for CVE-2023-0809

OS Trackers for CVE-2023-0809

vendor priority summary link
alpine — CVE-2023-0809: 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-2023-0809
debian not yet assigned CVE-2023-0809 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-2023-0809
gentoo low CVE-2023-0809: 1 GLSA(s) (202401-09), 1 atom(s) (app-misc/mosquitto); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-0809
redhat medium — https://access.redhat.com/security/cve/CVE-2023-0809
ubuntu medium CVE-2023-0809 medium priority: Ubuntu including 1 source packages (mosquitto), 11 status rows across 11 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 7, released 4. https://ubuntu.com/security/CVE-2023-0809

Affected software / configurations for CVE-2023-0809

Vendor Product Version Raw CPE
eclipse mosquitto < 2.0.16 cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*

References for CVE-2023-0809

cvelogic Threat Intelligence