CVE-2026-89586

Status: UPDATED  |  Advisory ID: CVE-2026-89586

Key Details

Affected Products, Subsystems & Sectors

What to Know

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. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References