---
id: CVE-2026-99037
title: 'dm-crypt: reject the lmk IV mode with AEAD ciphers'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dm-crypt: reject the lmk IV mode with AEAD ciphers

  A "capi:" table line that pairs an AEAD cipher with the lmk IV mode,
  for example "capi:gcm(aes)-lmk" with the integr…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 <
    9a0dab8a9d9975dec14a118b55cae2517aea5ca9
  - >-
    Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 <
    962ce265fbf5d87afeb78cf19c12e083ab0ffeb8
  - >-
    Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 <
    a1a875614dae43b43d311bb9e7a7a70eed78efe6
  - >-
    Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 <
    40ea7dfa8cd5f9aed72a55c9ca3008aee5880e6f
  - >-
    Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 <
    3195e0daf590683992edb4eed32269e569e04924
  - Linux 4.12
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T12:21:54.317Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99037'
references:
  - url: 'https://git.kernel.org/stable/c/9a0dab8a9d9975dec14a118b55cae2517aea5ca9'
  - url: 'https://git.kernel.org/stable/c/962ce265fbf5d87afeb78cf19c12e083ab0ffeb8'
  - url: 'https://git.kernel.org/stable/c/a1a875614dae43b43d311bb9e7a7a70eed78efe6'
  - url: 'https://git.kernel.org/stable/c/40ea7dfa8cd5f9aed72a55c9ca3008aee5880e6f'
  - url: 'https://git.kernel.org/stable/c/3195e0daf590683992edb4eed32269e569e04924'
tags:
  - cve.org
ingestedAt: '2026-10-23T13:24:55.528Z'
---

## Overview

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

dm-crypt: reject the lmk IV mode with AEAD ciphers

A "capi:" table line that pairs an AEAD cipher with the lmk IV mode,
for example "capi:gcm(aes)-lmk" with the integrity:28:aead option,
causes an oops when it is loaded. lmk sets tfms_count to 64, but
crypt_alloc_tfms_aead only allocates one transform, so crypt_setkey
reads past the end of the tfms_aead array and calls crypto_aead_setkey
on the values it finds there.

lmk exists for compatibility with Loop-AES, which uses CBC, so refuse
it with an AEAD cipher rather than allocate 64 AEAD transforms. The
check cannot go in crypt_iv_lmk_ctr with the other lmk checks, because
the IV constructor runs after crypt_set_key.

Note that this is not a security bug because the memory corruption can
only be triggered by root.

## Affected

- `Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 < 9a0dab8a9d9975dec14a118b55cae2517aea5ca9`
- `Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 < 962ce265fbf5d87afeb78cf19c12e083ab0ffeb8`
- `Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 < a1a875614dae43b43d311bb9e7a7a70eed78efe6`
- `Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 < 40ea7dfa8cd5f9aed72a55c9ca3008aee5880e6f`
- `Linux >= 33d2f09fcb357fd1861c4959d1d3505492bf91f8 < 3195e0daf590683992edb4eed32269e569e04924`
- `Linux 4.12`

## Remediation

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