CVE-2025-21738

System crash via unchecked ATA PIO buffer length

Published Feb 27, 2025 · Updated Aug 5, 2026

Out-of-bounds write in the Linux kernel allows local users to crash the system via a crafted SCSI_IOCTL_SEND_COMMAND ioctl. The ata_pio_sector() path transfers a full ATA sector into the scatter-gather buffer without checking that enough allocated space remains. Low-privileged local access and permission to issue the ioctl against an ATA device are required; the resulting random kernel-memory overwrite can interrupt the system.

CVSS severity5.5
Medium
EPSS probability0.22%
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 Linux kernel allows local users to crash the system via a crafted SCSI_IOCTL_SEND_COMMAND ioctl. The ata_pio_sector() path transfers a full ATA sector into the scatter-gather buffer without checking that enough allocated space remains. Low-privileged local access and permission to issue the ioctl against an ATA device are required; the resulting random kernel-memory overwrite can interrupt the system.

The record

CVE
CVE-2025-21738
Published
Feb 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=2.6.22
  2. Affected versionversion=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <0a17a9944b8d89ef03946121241870ac53ddaf45
  3. Affected versionversion=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <0dd5aade301a10f4b329fa7454fdcc2518741902
  4. Affected versionversion=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <6e74e53b34b6dec5a50e1404e2680852ec6768d2
  5. Affected versionversion=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <a8f8cf87059ed1905c2a5c72f8b39a4f57b11b4c
  6. Affected versionversion=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <d5e6e3000309359eae2a17117aa6e3c44897bf6c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.22; version=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <0a17a9944b8d89ef03946121241870ac53ddaf45; version=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <0dd5aade301a10f4b329fa7454fdcc2518741902; version=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <6e74e53b34b6dec5a50e1404e2680852ec6768d2; version=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <a8f8cf87059ed1905c2a5c72f8b39a4f57b11b4c; version=5a5dbd18a7496ed403f6f54bb20c955c65482fa5 <d5e6e3000309359eae2a17117aa6e3c44897bf6c

Published CVSS scores

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1499.004Application or System Exploitation

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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