CVE-2023-33656Public exploit

Service interruption via crafted MQTT packet memory leak

Published May 30, 2023 · Updated Jan 10, 2025

Memory leak in NanoMQ 0.17.2 allows local users to exhaust available memory by supplying a crafted MQTT packet. The message-handling code in message.c fails to release memory after processing the crafted input, allowing allocations to accumulate. Exploitation requires a local user to deliver the packet to a running broker; repeated input exhausts memory and interrupts the service.

CVSS severity5.5
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Memory leak in NanoMQ 0.17.2 allows local users to exhaust available memory by supplying a crafted MQTT packet. The message-handling code in message.c fails to release memory after processing the crafted input, allowing allocations to accumulate. Exploitation requires a local user to deliver the packet to a running broker; repeated input exhausts memory and interrupts the service.

The record

CVE
CVE-2023-33656
Published
May 30, 2023
Updated
Jan 10, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-770, CWE-770, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 10, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo