CVE-2021-47257

Kernel crash via mismatched IEEE 802.15.4 address mode

Published May 21, 2024 · Updated May 11, 2026

NULL pointer dereference in the Linux kernel allows local users to crash a host through a malformed IEEE 802.15.4 address request. The ieee802154_llsec_parse_dev_addr function accepts either address attribute before verifying that it matches the supplied mode, then dereferences the missing mode-specific attribute. A low-privileged local user must submit inconsistent generic-netlink address data; successful exploitation interrupts the host by crashing its kernel.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux kernel allows local users to crash a host through a malformed IEEE 802.15.4 address request. The ieee802154_llsec_parse_dev_addr function accepts either address attribute before verifying that it matches the supplied mode, then dereferences the missing mode-specific attribute. A low-privileged local user must submit inconsistent generic-netlink address data; successful exploitation interrupts the host by crashing its kernel.

The record

CVE
CVE-2021-47257
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=4.4
  2. Affected versionversion=a26c5fd7622d4951425131d54a8c99f076fe2068 <1f95741981c899c4724647291fec5faa3c777185
  3. Affected versionversion=a26c5fd7622d4951425131d54a8c99f076fe2068 <5f728ec65485625e30f46e5b4917ff023ad29ea0
  4. Affected versionversion=a26c5fd7622d4951425131d54a8c99f076fe2068 <9fdd04918a452980631ecc499317881c1d120b70
  5. Affected versionversion=a26c5fd7622d4951425131d54a8c99f076fe2068 <c6998ccfefa652bac3f9b236821e392af43efa1e
  6. Affected versionversion=a26c5fd7622d4951425131d54a8c99f076fe2068 <c7836de2cadd88bc2f20f2c5a3d4ef4c73aef627
  7. Affected versionversion=a26c5fd7622d4951425131d54a8c99f076fe2068 <d0f47648b87b6d5f204cb7f3cbce6d36dab85a67
  8. Affected versionversion=a26c5fd7622d4951425131d54a8c99f076fe2068 <fdd51e34f45311ab6e48d2147cbc2904731b9993

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.4; version=a26c5fd7622d4951425131d54a8c99f076fe2068 <1f95741981c899c4724647291fec5faa3c777185; version=a26c5fd7622d4951425131d54a8c99f076fe2068 <5f728ec65485625e30f46e5b4917ff023ad29ea0; version=a26c5fd7622d4951425131d54a8c99f076fe2068 <9fdd04918a452980631ecc499317881c1d120b70; version=a26c5fd7622d4951425131d54a8c99f076fe2068 <c6998ccfefa652bac3f9b236821e392af43efa1e; version=a26c5fd7622d4951425131d54a8c99f076fe2068 <c7836de2cadd88bc2f20f2c5a3d4ef4c73aef627; version=a26c5fd7622d4951425131d54a8c99f076fe2068 <d0f47648b87b6d5f204cb7f3cbce6d36dab85a67; version=a26c5fd7622d4951425131d54a8c99f076fe2068 <fdd51e34f45311ab6e48d2147cbc2904731b9993

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5CanonicalCVSS:3.1/AV:L/AC:L/PR:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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