Use-after-free in Linux kernel - CVE-2026-64563

Vulnerability identifier: #VU140934

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-2026-64563

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 a use-after-free in rhashtable_walk_next in the rhashtable iterator logic when resuming multi-fragment rhashtable walks across walk_stop and walk_start boundaries after a table restart. A local user can trigger a stale iterator pointer dereference to cause a denial of service.

Concrete affected call paths include netlink_diag and TIPC.

Linux kernel
Debian Linux
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
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
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
kernel (Red Hat package)
kernel-rt (Red Hat package)
linux (Debian package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - update to 4.18.0-553.160.1.el8_10
kernel-rt (Red Hat package) - update to 4.18.0-553.160.1.rt7.501.el8_10
linux (Debian package) - update to 6.12.101-1

• https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3
• https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3
• https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456

• Use-after-free in Linux kernel lib
• Debian update for linux
• Red Hat Enterprise Linux 8 update for kernel-rt
• Red Hat Enterprise Linux 8 update for kernel