CVE-2025-21738: Linux kernel · ata: libata-sff: Ensure that we cannot write outside the allocated buffer
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1032.34~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1032.34~22.04.1, 6.8.0-1034.39~22.04.1, 6.8.0-1033.35~22.04.1 +30
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Feb 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7521-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7652-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7653-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-7737-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: ata: libata-sff: Ensure that we cannot write outside the allocated buffer reveliofuzzing reported that a SCSI_IOCTL_SEND_COMMAND ioctl with out_len set to 0xd42, SCSI command set to ATA_16 PASS-THROUGH, ATA command set to ATA_NOP, and protocol set to ATA_PROT_PIO, can cause ata_pio_sector() to write outside the allocated buffer, overwriting random memory. While a ATA device is supposed to abort a ATA_NOP command, there does seem to be a bug either in libata-sff or QEMU, where either this status is not set, or the status is cleared before read by ata_sff_hsm_move(). Anyway, that is most likely a separate bug. Looking at __atapi_pio_bytes(), it already has a safety check to ensure that __atapi_pio_bytes() cannot write outside the allocated buffer. Add a similar check to ata_pio_sector(), such that also ata_pio_sector() cannot write outside the allocated buffer.
References
- ubuntu.com/security/CVE-2025-21738 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21738 (opens in a new tab)
- git.kernel.org/linus/6e74e53b34b6dec5a50e1404e2680852ec6768d2 (opens in a new tab)
- git.kernel.org/stable/c/0a17a9944b8d89ef03946121241870ac53ddaf45 (opens in a new tab)
- git.kernel.org/stable/c/0dd5aade301a10f4b329fa7454fdcc2518741902 (opens in a new tab)
- git.kernel.org/stable/c/6e74e53b34b6dec5a50e1404e2680852ec6768d2 (opens in a new tab)
- git.kernel.org/stable/c/a8f8cf87059ed1905c2a5c72f8b39a4f57b11b4c (opens in a new tab)
- git.kernel.org/stable/c/d5e6e3000309359eae2a17117aa6e3c44897bf6c (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7652-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7653-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-7737-1 (opens in a new tab)