How severe is CVE-2023-28366?

CVE-2023-28366 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-28366 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-28366?

CVE-2023-28366 affects Eclipse Mosquitto. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-28366?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-28366 published?

CVE-2023-28366 was published on 2023-09-01 and last updated on 2026-06-17.

CVE-2023-28366

CVE-2023-28366 is a high-severity vulnerability in Eclipse Mosquitto with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-401.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-401
Affected product: Eclipse Mosquitto
Published: 2023-09-01
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2023-28366?: CVE-2023-28366 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-28366 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-28366?: CVE-2023-28366 affects Eclipse Mosquitto. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-28366?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-28366 published?: CVE-2023-28366 was published on 2023-09-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*

More vulnerabilities in Eclipse Mosquitto

CVE-2024-10525 — Critical (CVSS 9.8): In Eclipse Mosquitto, from version 1.3.2 through 2.0.18, if a malicious broker sends a crafted SUBACK packet with no…
CVE-2018-12551 — High (CVSS 8.1): When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for authentication, any…
CVE-2018-12550 — High (CVSS 8.1): When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use an ACL file, and that ACL file is empty,…
CVE-2024-8376 — High (CVSS 7.5): In Eclipse Mosquitto up to version 2.0.18a, an attacker can achieve memory leaking, segmentation fault or…
CVE-2023-5632 — High (CVSS 7.5): In Eclipse Mosquito before and including 2.0.5, establishing a connection to the mosquitto server without sending data…
CVE-2021-41039 — High (CVSS 7.5): In versions 1.6 to 2.0.11 of Eclipse Mosquitto, an MQTT v5 client connecting with a large number of user-property…

All CVEs affecting Eclipse Mosquitto →

Other CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities

CVE-2022-0742 — Critical (CVSS 9.1): Memory leak in icmp6 implementation in Linux Kernel 5.13+ allows a remote attacker to DoS a host by making it go…
CVE-2024-25450 — High (CVSS 8.8): imlib2 v1.9.1 was discovered to mishandle memory allocation in the function init_imlib_fonts().
CVE-2023-33718 — High (CVSS 8.8): mp4v2 v2.1.3 was discovered to contain a memory leak via MP4File::ReadString() at mp4file_io.cpp
CVE-2021-40633 — High (CVSS 8.8): A memory leak (out-of-memory) in gif2rgb in util/gif2rgb.c in giflib 5.1.4 allows remote attackers trigger an out of…
CVE-2021-3492 — High (CVSS 8.8): Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring…
CVE-2019-17340 — High (CVSS 8.8): An issue was discovered in Xen through 4.11.x allowing x86 guest OS users to cause a denial of service or gain…

Browse all CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

182.95.185.158 (ipv4-addr)
182.95.101.182 (ipv4-addr)
182.76.86.130 (ipv4-addr)
128.185.201.170 (ipv4-addr)
125.19.157.158 (ipv4-addr)
98.122.215.23 (ipv4-addr)
27.123.111.110 (ipv4-addr)
182.95.48.154 (ipv4-addr)