CVE-2026-89586
Published: September 15, 2026Last modified: September 28, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 8.2 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | LOW |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Vulnerable (6.1.182-r0) |
| 25 LTS | linux-lts | Fixed (6.12.111-r0) | |
| Stream | linux-lts | Fixed (6.18.53-r0) |
References
- https://git.kernel.org/stable/c/04e2befe25792f2e90097f284d7e86fc6bcfe928
- https://git.kernel.org/stable/c/07975b8daa3b0ab3cbc02cc48ea7bc48fadcec53
- https://git.kernel.org/stable/c/07baa310ea3224a7044b1ca84796bb37a235af1f
- https://git.kernel.org/stable/c/4a4268a0b0a595bd9534cf9c7fda93775a7d8a0d
- https://git.kernel.org/stable/c/79cce911e623c0baa0fde307ce3a434e084b881a
- https://git.kernel.org/stable/c/977554ed91b54075fbc0bac536316b4841ef6258
- https://git.kernel.org/stable/c/b7b5ab2df325ffbbad7ca2debaa071e024d68cb5
- https://git.kernel.org/stable/c/c2e3dccd6870659851eaa4c12ab16418b8e3040a