CVE-2023-24821Network attack vector

Device hang via undersized 6LoWPAN fragments

Published Apr 24, 2023 · Updated Feb 4, 2025

Integer underflow in RIOT before 2022.10 allows remote attackers to hang devices by sending undersized 6LoWPAN fragments. The _6lo_frag_size function subtracts a four-byte header from pkt->size without first checking its length, then _rbuf_add passes the wrapped size to memcpy. Fragmented IP datagram support must be enabled, and the resulting out-of-bounds write causes an unhandled hard fault that leaves the device stuck until reset.

CVSS severity7.5
High
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in RIOT before 2022.10 allows remote attackers to hang devices by sending undersized 6LoWPAN fragments. The _6lo_frag_size function subtracts a four-byte header from pkt->size without first checking its length, then _rbuf_add passes the wrapped size to memcpy. Fragmented IP datagram support must be enabled, and the resulting out-of-bounds write causes an unhandled hard fault that leaves the device stuck until reset.

The record

CVE
CVE-2023-24821
Published
Apr 24, 2023
Updated
Feb 4, 2025
Vendor
RIOT-OS
Product
RIOT
Classifications
CWE-787, CWE-191, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 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=< 2022.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

RIOT-OS · RIOTversion=< 2022.10

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5GitHubCVSS: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-191Integer Underflow (Wrap or Wraparound)
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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