Uncontrolled Memory Allocation in Linux kernel - CVE-2026-93186

Vulnerability identifier: #VU150815

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-93186

CWE-ID: CWE-789

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to uncontrolled memory allocation in the CXL mailbox command constructor cxl_mbox_cmd_ctor() when processing CXL_MEM_SEND_COMMAND requests with an oversized output size. A local user can submit a command with a large output size to cause a denial of service.

A system panic requires panic_on_warn=1.

Linux kernel
Debian Linux
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux (Debian package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/31d4841eca7c4b75751ca96d24339e19303337f2
• https://git.kernel.org/stable/c/8a13db9f899d149c3aab24abcb668121cfda5a4f
• https://git.kernel.org/stable/c/b4e11c731d6bee3b87315e055a1ca417c92dc1fc
• https://git.kernel.org/stable/c/f5d2bbf0300f46307948864fbb97bce5097f4fe2

• Uncontrolled Memory Allocation in Linux kernel cxl core driver
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more