CVE-2026-89586

ata: libata-scsi: fix DSM TRIM for sector sizes larger than 2048 bytes

Published Sep 11, 2026 CVSS 3.1 · 8.2 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

ata: libata-scsi: fix DSM TRIM for sector sizes larger than 2048 bytes

ata_scsi_write_same_xlat() translates a SCSI WRITE SAME command with the
UNMAP bit set into an ATA DATA SET MANAGEMENT TRIM command. The TRIM
descriptor is built by ata_format_dsm_trim_descr() into the 2048-byte
ata_scsi_rbuf staging buffer, and the number of bytes copied is compared
against the logical sector size by the caller:

size = ata_format_dsm_trim_descr(scmd, trmax, block, n_block);
if (size != len) /* len == sdp->sector_size */
goto invalid_param_len;

ata_format_dsm_trim_descr() clamps the copy length to ATA_SCSI_RBUF_SIZE
(2048). On a device whose logical sector size exceeds that (e.g. a 4Kn
device, where sector_size == 4096) the function can never return more than
2048, while the caller expects it to return sector_size. The comparison
therefore always fails, so every TRIM is rejected with "Parameter list
length error" and WARN_ON() splats on each attempt. TRIM / discard is
thus completely broken on such devices.

The descriptor was incorrectly sized from the logical sector size. A DSM
TRIM payload is a list of 512-byte pages, each holding up to
ATA_MAX_TRIM_RNUM (64) LBA Range Entries, and is independent of the logical
sector size. The Block Limits VPD page already advertises a single such
page as the maximum WRITE SAME length (65535 * ATA_MAX_TRIM_RNUM logical
blocks), so the block layer never sends a request that needs more than one
page.

Emit exactly one 512-byte page, independent of the logical sector size,
and transfer only that page (COUNT == 1). For a 512-byte-sector device
this is unchanged; devices with larger logical sectors now work instead of
failing every TRIM.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4817-1 linux-6.12 security update
Debian DLA Debian DLA DLA-4841-1 linux security update
Debian DSA Debian DSA DSA-6528-1 linux security update
Ubuntu USN Ubuntu USN USN-8961-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9002-1 Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9022-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9023-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9024-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9026-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9029-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-9039-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-9040-1 Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'}

Type Values Removed Values Added
Weaknesses CWE-20
Type Values Removed Values Added
Weaknesses CWE-130
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-20
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ata: libata-scsi: fix DSM TRIM for sector sizes larger than 2048 bytes ata_scsi_write_same_xlat() translates a SCSI WRITE SAME command with the UNMAP bit set into an ATA DATA SET MANAGEMENT TRIM command. The TRIM descriptor is built by ata_format_dsm_trim_descr() into the 2048-byte ata_scsi_rbuf staging buffer, and the number of bytes copied is compared against the logical sector size by the caller: size = ata_format_dsm_trim_descr(scmd, trmax, block, n_block); if (size != len) /* len == sdp->sector_size */ goto invalid_param_len; ata_format_dsm_trim_descr() clamps the copy length to ATA_SCSI_RBUF_SIZE (2048). On a device whose logical sector size exceeds that (e.g. a 4Kn device, where sector_size == 4096) the function can never return more than 2048, while the caller expects it to return sector_size. The comparison therefore always fails, so every TRIM is rejected with "Parameter list length error" and WARN_ON() splats on each attempt. TRIM / discard is thus completely broken on such devices. The descriptor was incorrectly sized from the logical sector size. A DSM TRIM payload is a list of 512-byte pages, each holding up to ATA_MAX_TRIM_RNUM (64) LBA Range Entries, and is independent of the logical sector size. The Block Limits VPD page already advertises a single such page as the maximum WRITE SAME length (65535 * ATA_MAX_TRIM_RNUM logical blocks), so the block layer never sends a request that needs more than one page. Emit exactly one 512-byte page, independent of the logical sector size, and transfer only that page (COUNT == 1). For a 512-byte-sector device this is unchanged; devices with larger logical sectors now work instead of failing every TRIM.
Title ata: libata-scsi: fix DSM TRIM for sector sizes larger than 2048 bytes
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 8:49 AM
Reserved
Sep 11, 2026, 7:38 PM
Status
Received
Published
Sep 11, 2026, 8:19 PM
Modified
Oct 19, 2026, 9:17 AM
Severity
Moderate
Public date
Sep 11, 2026, 7:44 PM