Use-after-free in Linux kernel - CVE-2026-64438

Vulnerability identifier: #VU139501

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-2026-64438

CWE-ID: CWE-416

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 use-after-free in the VF2PF response workqueue handling in the intel_qat SR-IOV implementation when processing VF2PF messages during SR-IOV teardown. A local user can trigger concurrent VF2PF work so that a queued or in-flight worker dereferences freed per-VF state to cause a denial of service.

The issue occurs because PF-side response work stores a raw pointer to per-VF state that may be freed by adf_disable_sriov() before queued work completes.

Linux kernel
Debian Linux
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Ubuntu
kernel (Red Hat package)
linux (Debian package)
linux (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - update to 6.12.0-211.50.1.el10_2
linux (Debian package) - update to 6.12.100-1
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-gcp-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

• https://git.kernel.org/stable/c/218c2836b3987f3fa1d9eac505462cded0821e4c
• https://git.kernel.org/stable/c/277281c10c63791067d24d421f7c43a15faa9096
• https://git.kernel.org/stable/c/446b4d77599cf1a168573f7fb32a4a6aa4f09219
• https://git.kernel.org/stable/c/49cd5ac6de8de39a14ead609bb552d372d5602cd
• https://git.kernel.org/stable/c/51144032248cc4ea22917370565650670b8b4e9b
• https://git.kernel.org/stable/c/5d916c1eae1933511a69bffe243b4ee5d7da399c
• https://git.kernel.org/stable/c/6e92b28cd74fa433658efeadf21b9d4b01023d7d
• https://git.kernel.org/stable/c/f344a369d0380d54c8d6c8d24734a78dd5a89817

• Use-after-free in Linux kernel qat qat_common driver
• Debian update for linux
• Red Hat Enterprise Linux 10 update for kernel
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0