CVE-2019-11779

In Eclipse Mosquitto 1.5.0 to 1.6.5 inclusive, if a malicious MQTT client sends a SUBSCRIBE packet containing a topic that consists of approximately 65400 or more '/' characters, i.e. the topic hierarchy separator, then a stack overflow will occur.

Published: 2019-09-19 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-11779 is rated Moderate Risk (50.5/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.74%). 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-2019-11779

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 14.84% 2.74% -12.10%
2 2026-06-14 16.33% 14.84% -1.49%
3 2026-05-26 — 16.33% —

Full EPSS history (28 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-11779

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/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:L)
A normal user session is enough; they don’t have to be admin.
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.
 2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2019-11779

OS Trackers for CVE-2019-11779

vendor priority summary link
alpine medium CVE-2019-11779: 1 source package rows (mosquitto); 20 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 10. https://security.alpinelinux.org/vuln/CVE-2019-11779
debian not yet assigned CVE-2019-11779 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-2019-11779
ubuntu medium CVE-2019-11779 medium priority: Ubuntu including 1 source packages (mosquitto), 5 status rows across 5 suites (bionic, disco, trusty, upstream, xenial): not-affected 3, released 2. https://ubuntu.com/security/CVE-2019-11779

Affected software / configurations for CVE-2019-11779

Vendor Product Version Raw CPE
eclipse mosquitto >= 1.5, < 1.5.9 cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*
eclipse mosquitto >= 1.6, < 1.6.6 cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*
canonical ubuntu_linux 19.04 cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:*
opensuse backports_sle 15.0 cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
fedoraproject fedora 29 cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
fedoraproject fedora 30 cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2019-11779

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00077.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00008.html Mailing List Third Party Advisory
https://bugs.eclipse.org/bugs/show_bug.cgi?id=551160 Vendor Advisory
https://lists.debian.org/debian-lts-announce/2019/10/msg00035.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D4WMHIM64Q35NGTR6R3ILZUL4MA4ANB5/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HFWQBNFTAVHPUYNGYO2TCPF5PCSWC2Z7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JWNVTFA2CKXERXRYPYE2YFTZP4GNBGYY/
https://seclists.org/bugtraq/2019/Nov/25 Mailing List Third Party Advisory
https://usn.ubuntu.com/4137-1/ Third Party Advisory
https://www.debian.org/security/2019/dsa-4570 Third Party Advisory
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