CVE-2021-47633

Kernel memory corruption via unchecked calibration-curve index

Published Feb 26, 2025 · Updated May 11, 2026

Out-of-bounds write in the ath5k driver in Linux allows physically proximate attackers to corrupt kernel memory through EEPROM data. The ath5k_eeprom_convert_pcal_info_5111 loop can leave idx equal to AR5K_EEPROM_N_PD_CURVES, then uses it to select pd_curves and performs multiple writes through the out-of-range pointer. Triggering requires a supported Atheros wireless device with calibration data that selects no power-detector curve; the observed result is a slab overwrite during module loading.

CVSS severity5.4
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in the ath5k driver in Linux allows physically proximate attackers to corrupt kernel memory through EEPROM data. The ath5k_eeprom_convert_pcal_info_5111 loop can leave idx equal to AR5K_EEPROM_N_PD_CURVES, then uses it to select pd_curves and performs multiple writes through the out-of-range pointer. Triggering requires a supported Atheros wireless device with calibration data that selects no power-detector curve; the observed result is a slab overwrite during module loading.

The record

CVE
CVE-2021-47633
Published
Feb 26, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2025CVE 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

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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=2.6.30
  2. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <25efc5d03455c3839249bc77fce5e29ecb54677e
  3. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <564d4eceb97eaf381dd6ef6470b06377bb50c95a
  4. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <9d7d83d0399e23d66fd431b553842a84ac10398f
  5. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <be2f81024e7981565d90a4c9ca3067d11b6bca7f
  6. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <c4e2f577271e158d87a916afb4e87415a88ce856
  7. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <cbd96d6cad6625feba9c8d101ed4977d53e82f8e
  8. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <ed3dfdaa8b5f0579eabfc1c5818eed30cfe1fe84
  9. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <f4de974019a0adf34d0e7de6b86252f1bd266b06
  10. Affected versionversion=8e218fb24faef0bfe95bc91b3c05261e20439527 <fc8f7752a82f4accb99c0f1a868906ba1eb7b86f

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.30; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <25efc5d03455c3839249bc77fce5e29ecb54677e; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <564d4eceb97eaf381dd6ef6470b06377bb50c95a; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <9d7d83d0399e23d66fd431b553842a84ac10398f; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <be2f81024e7981565d90a4c9ca3067d11b6bca7f; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <c4e2f577271e158d87a916afb4e87415a88ce856; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <cbd96d6cad6625feba9c8d101ed4977d53e82f8e; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <ed3dfdaa8b5f0579eabfc1c5818eed30cfe1fe84; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <f4de974019a0adf34d0e7de6b86252f1bd266b06; version=8e218fb24faef0bfe95bc91b3c05261e20439527 <fc8f7752a82f4accb99c0f1a868906ba1eb7b86f

Published CVSS scores

7.1UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
5.4UbuntuCVSS:4.0/AV:P/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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-125Out-of-bounds Read

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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