---
id: CVE-2026-89586
title: 'ata: libata-scsi: fix DSM TRIM for sector sizes larger than 2048 bytes'
summary: |-
  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 A…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-130
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    07975b8daa3b0ab3cbc02cc48ea7bc48fadcec53
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    b7b5ab2df325ffbbad7ca2debaa071e024d68cb5
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    07baa310ea3224a7044b1ca84796bb37a235af1f
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    977554ed91b54075fbc0bac536316b4841ef6258
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    04e2befe25792f2e90097f284d7e86fc6bcfe928
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    c2e3dccd6870659851eaa4c12ab16418b8e3040a
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    4a4268a0b0a595bd9534cf9c7fda93775a7d8a0d
  - >-
    Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff <
    79cce911e623c0baa0fde307ce3a434e084b881a
  - Linux 4.9
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-16T19:24:31.774727Z'
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:49:18.983Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89586'
references:
  - url: 'https://git.kernel.org/stable/c/07975b8daa3b0ab3cbc02cc48ea7bc48fadcec53'
  - url: 'https://git.kernel.org/stable/c/b7b5ab2df325ffbbad7ca2debaa071e024d68cb5'
  - url: 'https://git.kernel.org/stable/c/07baa310ea3224a7044b1ca84796bb37a235af1f'
  - url: 'https://git.kernel.org/stable/c/977554ed91b54075fbc0bac536316b4841ef6258'
  - url: 'https://git.kernel.org/stable/c/04e2befe25792f2e90097f284d7e86fc6bcfe928'
  - url: 'https://git.kernel.org/stable/c/c2e3dccd6870659851eaa4c12ab16418b8e3040a'
  - url: 'https://git.kernel.org/stable/c/4a4268a0b0a595bd9534cf9c7fda93775a7d8a0d'
  - url: 'https://git.kernel.org/stable/c/79cce911e623c0baa0fde307ce3a434e084b881a'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89586.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89586'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532420'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89586'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89586'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89586.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00615
epssPercentile: 0.49256
scores:
  cna: 8.2
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.451Z'
---

## Overview

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.

## Affected

- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < 07975b8daa3b0ab3cbc02cc48ea7bc48fadcec53`
- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < b7b5ab2df325ffbbad7ca2debaa071e024d68cb5`
- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < 07baa310ea3224a7044b1ca84796bb37a235af1f`
- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < 977554ed91b54075fbc0bac536316b4841ef6258`
- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < 04e2befe25792f2e90097f284d7e86fc6bcfe928`
- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < c2e3dccd6870659851eaa4c12ab16418b8e3040a`
- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < 4a4268a0b0a595bd9534cf9c7fda93775a7d8a0d`
- `Linux >= ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff < 79cce911e623c0baa0fde307ce3a434e084b881a`
- `Linux 4.9`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89586.json)