CVE-2025-21738: ata: libata-sff: Ensure that we cannot write outside the allocated buffer

mediumCVSS 5.5CVE-2025-21738

CSIRTS triage

vendor: Linux product: Linux Kernel Memory corruption

What: Buffer overflow vulnerability in the libata-sff driver allowing writes outside allocated memory.
Who is affected: Systems using legacy SATA controllers relying on the libata-sff driver.
Urgency: Medium priority; buffer overflow can cause data corruption or denial of service.
Action: Apply kernel patch ensuring proper buffer bounds checking in the libata-sff write code path.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.5
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21738

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2025-217380.22% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 13% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2025-21738	coverage & exploitation status	NVD · CVE.org

Recent advisories for ata

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-45855: ata: libata-scsi: avoid Non-NCQ command starvationmsrc · 2026-08-06