CVE-2026-99037: Linux kernel · dm-crypt: reject the lmk IV mode with AEAD ciphers
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 28 Oct 2026, 01:45 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix has been implemented in the Linux kernel to reject the lmk IV mode when used with AEAD ciphers, preventing the out-of-bounds access. Users should update to fixed kernel versions. Since root privileges are required to trigger this issue, restricting root access and applying kernel updates are effective mitigations.
Description
A vulnerability in the Linux kernel's dm-crypt subsystem involves improper handling of the lmk IV mode when used with AEAD ciphers. Specifically, pairing an AEAD cipher with the lmk IV mode causes a kernel oops due to out-of-bounds memory access. This issue arises because lmk sets a transform count of 64, but only one transform is allocated, leading to memory corruption during key setup. The flaw is not exploitable by unprivileged users as root privileges are required to trigger it.
References
- ubuntu.com/security/CVE-2026-99037 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99037 (opens in a new tab)
- git.kernel.org/stable/c/3195e0daf590683992edb4eed32269e569e04924 (opens in a new tab)
- git.kernel.org/stable/c/40ea7dfa8cd5f9aed72a55c9ca3008aee5880e6f (opens in a new tab)
- git.kernel.org/stable/c/962ce265fbf5d87afeb78cf19c12e083ab0ffeb8 (opens in a new tab)
- git.kernel.org/stable/c/9a0dab8a9d9975dec14a118b55cae2517aea5ca9 (opens in a new tab)
- git.kernel.org/stable/c/a1a875614dae43b43d311bb9e7a7a70eed78efe6 (opens in a new tab)