---
id: CVE-2026-93785
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: validate idmap key payload length

  The cifs.idmap key type stores its payload length in key->datalen, which
  is limited to U16_MAX
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: validate idmap key payload length

  The cifs.idmap key type stores its payload length in key->datalen, which
  is limited to U16_MAX.  Accepting a larger key payload…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    6cfeef221ac00d63c07f6122f58e6159bde69ca0
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    8b12f65d7caf16d124098cb4895a203367d35b57
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    455488cd5054bcc59db40fa1cc2c004031a5b2a5
  - Linux < 6.12.111
  - Linux < 6.18.53
  - Linux (all versions)
published: '2026-09-24'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T13:17:19.053'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93785'
references:
  - url: 'https://git.kernel.org/stable/c/455488cd5054bcc59db40fa1cc2c004031a5b2a5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6cfeef221ac00d63c07f6122f58e6159bde69ca0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8b12f65d7caf16d124098cb4895a203367d35b57'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-24T16:47:15.903Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

cifs: validate idmap key payload length

The cifs.idmap key type stores its payload length in key->datalen, which
is limited to U16_MAX.  Accepting a larger key payload truncates the
recorded length and can make later users interpret the payload using
inconsistent bounds.

Reject oversized preparsed payloads before allocating or copying them.
This keeps key->datalen consistent with the stored data for both inline
and separately allocated idmap payloads.

## Remediation

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