Out-of-bounds write in Linux kernel - CVE-2026-64293

Vulnerability identifier: #VU139679

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64293

CWE-ID: CWE-787

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to overwrite memory in a user-supplied buffer.

The vulnerability exists due to an out-of-bounds write in iommufd_veventq_fops_read() when reading normal vEVENT records. A local user can trigger the function with a crafted buffer size and event data length to overwrite memory in a user-supplied buffer.

This affects 32-bit systems because the bounds check uses the size of a pointer instead of the full header size.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/04a177f91160ee18da98f5689482cf0f589ec869
• https://git.kernel.org/stable/c/0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72
• https://git.kernel.org/stable/c/be93d186ae88a92e7aa77e122d4e661fa57b1e39

• Out-of-bounds write in Linux kernel iommu iommufd driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0