Out-of-bounds read in Linux kernel - CVE-2026-74573

Vulnerability identifier: #VU143204

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-2026-74573

CWE-ID: CWE-125

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 an out-of-bounds read in arm_vsmmu_vsid_to_sid() in the arm-smmu-v3 iommufd code when initializing or using a vDEVICE backed by a device with no stream IDs. A local user can create or use such a vDEVICE to cause a denial of service.

The issue occurs because the code assumes a device has exactly one stream ID.

Linux kernel
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)

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

• https://git.kernel.org/stable/c/0acbc621341aca4eb94d9c2f43e1ab273ff088f0
• https://git.kernel.org/stable/c/3808bab5d95ae79e333e11f6a73d178e084c645d
• https://git.kernel.org/stable/c/c3b8ee84a965058b41275069d4696f37a8b14bf6

• Out-of-bounds read in Linux kernel arm arm-smmu-v3 driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more