VulnerabilityPublished 17 Apr 2024Updated 2 Aug 2024

CVE-2024-31040: nanomq · Buffer Overflow

Affects nanomqSource CVE Database V5

Not known to be exploited · CVSS 2.7 Low.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score

2.7Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Apr 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubnanomq/nanomq`pkg:github/nanomq/nanomq`Other threats	Affected =0.21.7	Fixed in–

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AI-suggested

To mitigate CVE-2024-31040, organizations should: 1) Monitor NanoMQ vendor channels and security advisories for official patches or updates addressing this vulnerability and apply them promptly once available. 2) Restrict network access to the NanoMQ broker to trusted and authenticated users only, minimizing exposure to untrusted networks or users. 3) Implement strict input validation and filtering at network boundaries or MQTT gateways to detect and block malformed or suspicious MQTT messages containing crafted hexstreams. 4) Employ runtime protections such as process isolation, resource limits, and watchdog timers to detect and recover from broker crashes quickly. 5) Conduct regular security assessments and fuzz testing on MQTT message handling components to identify similar vulnerabilities proactively. 6) Consider upgrading to newer versions of NanoMQ if they include security improvements or alternative MQTT brokers with robust security features if patching is delayed. 7) Maintain comprehensive logging and monitoring of MQTT broker activity to detect anomalous message patterns or repeated crashes indicative of exploitation attempts.

Description

Buffer Overflow vulnerability in the get_var_integer function in mqtt_parser.c in NanoMQ 0.21.7 allows remote attackers to cause a denial of service via a series of specially crafted hexstreams.

Impact

The primary impact of CVE-2024-31040 is a denial of service condition caused by crashing the NanoMQ broker when processing malicious MQTT messages. This can disrupt message delivery and availability of IoT or messaging services relying on NanoMQ. While confidentiality and integrity are not directly affected, service outages can have operational consequences, especially in environments where continuous MQTT communication is critical, such as industrial control systems, smart home devices, or telemetry platforms. Organizations using NanoMQ 0.21.7 or similar vulnerable versions may experience downtime or degraded service quality. The requirement for privileges (PR:H) limits exploitation to authenticated or semi-trusted users, reducing the risk of widespread remote attacks but not eliminating insider or compromised user threats. The lack of known exploits in the wild suggests limited active targeting currently, but the vulnerability could be leveraged in targeted attacks or penetration testing scenarios.

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #11
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
Docker Security (opens in a new tab)
XML Security (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.1 (opens in a new tab)
V14.1.2 (opens in a new tab)
V13.3.1 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Overflow Buffers (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Filter Failure through Buffer Overflow (opens in a new tab)
MIME Conversion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/nanomq/nanomq/issues/1720 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Feb 2026, 16:43 UTC

WeaknessesCWE-120

Technical details

References

Community reviews

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