CVE-2024-31031Public exploitNetwork attack vector

Service interruption via token offset overflow

Published Apr 17, 2024 · Updated Nov 4, 2025

Integer overflow in libcoap 4.3.4 allows remote attackers to interrupt CoAP services by sending a crafted sequence of messages. In coap_update_token, an unsigned offset added during a token-address calculation wraps below the base pointer after the message sequence. No authentication or user interaction is required; the network-processing path reaches undefined behavior with availability impact.

CVSS severity7.5
High
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in libcoap 4.3.4 allows remote attackers to interrupt CoAP services by sending a crafted sequence of messages. In coap_update_token, an unsigned offset added during a token-address calculation wraps below the base pointer after the message sequence. No authentication or user interaction is required; the network-processing path reaches undefined behavior with availability impact.

The record

CVE
CVE-2024-31031
Published
Apr 17, 2024
Updated
Nov 4, 2025
Vendor
libcoap
Product
libcoap
Classifications
CWE-190, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 17, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record 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=4.3.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

libcoap · libcoapversion=4.3.4

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499Endpoint Denial of Service

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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