CVE-2024-40494Public exploitNetwork attack vector

Code execution via unchecked CoAP option read

Published Oct 22, 2024 · Updated Oct 23, 2024

Stack buffer overflow in FreeCoAP 0.7 allows remote attackers to execute arbitrary code or crash a server via a crafted CoAP packet. In coap_msg_parse_ops, the option loop reads p[0] before checking whether len is zero, so a packet that exhausts the receive buffer triggers a one-byte out-of-bounds stack read. No authentication or user interaction is required; reachable CoAP server and proxy processes are exposed to code execution or a crash.

CVSS severity9.8
Critical
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in FreeCoAP 0.7 allows remote attackers to execute arbitrary code or crash a server via a crafted CoAP packet. In coap_msg_parse_ops, the option loop reads p[0] before checking whether len is zero, so a packet that exhausts the receive buffer triggers a one-byte out-of-bounds stack read. No authentication or user interaction is required; reachable CoAP server and proxy processes are exposed to code execution or a crash.

The record

CVE
CVE-2024-40494
Published
Oct 22, 2024
Updated
Oct 23, 2024
Vendor
Keith Cullen
Product
FreeCoAP
Classifications
CWE-120, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 22, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 23, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Keith Cullen · FreeCoAPversion=0.7

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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No observations available

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

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1190Exploit Public-Facing Application

Public exploit references

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

Technologies

Your stack

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Your stack

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