CVE-2021-33889

Code execution or daemon crash via metric_len mismatch

Published Jul 2, 2021 · Updated Aug 4, 2024

Stack-based buffer overflow in OpenThread wpantund through 2021-07-02 allows physically proximate attackers to execute code or crash the daemon. The unpack_link_metrics_as_val_map parser stores metric_len in a 16-bit stack variable while the Spinel decoder writes a 32-bit value into it, overwriting two adjacent bytes. Device access is required to supply crafted NCP data; successful exploitation executes code in the daemon context or interrupts the service.

CVSS severity6.8
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in OpenThread wpantund through 2021-07-02 allows physically proximate attackers to execute code or crash the daemon. The unpack_link_metrics_as_val_map parser stores metric_len in a 16-bit stack variable while the Spinel decoder writes a 32-bit value into it, overwriting two adjacent bytes. Device access is required to supply crafted NCP data; successful exploitation executes code in the daemon context or interrupts the service.

The record

CVE
CVE-2021-33889
Published
Jul 2, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.8NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.6NVDAV:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

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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