CVE-2021-27697Public exploitNetwork attack vector

Node crash via unchecked RPL option length

Published Apr 6, 2021 · Updated Aug 3, 2024

Buffer overflow in RIOT-OS 2021.01 GNRC RPL validation allows remote attackers to crash a node via a crafted IPv6 RPL control packet. The gnrc_rpl_validation_options() function advances through packed option structures without first checking the remaining packet length, then reads an option type or length beyond the allocated buffer. The GNRC RPL module must be enabled and receive the packet; the demonstrated consequence is an out-of-bounds read that aborts the node.

CVSS severity9.8
Critical
EPSS probability1.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in RIOT-OS 2021.01 GNRC RPL validation allows remote attackers to crash a node via a crafted IPv6 RPL control packet. The gnrc_rpl_validation_options() function advances through packed option structures without first checking the remaining packet length, then reads an option type or length beyond the allocated buffer. The GNRC RPL module must be enabled and receive the packet; the demonstrated consequence is an out-of-bounds read that aborts the node.

The record

CVE
CVE-2021-27697
Published
Apr 6, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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')
T1499.004Application or System Exploitation

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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