Use-after-free in Linux kernel - CVE-2026-64300

Vulnerability identifier: #VU139695

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-2026-64300

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a use-after-free condition.

The vulnerability exists due to a use-after-free in map_range() in the perf subsystem when mapping auxiliary buffer pages shared between events. A local user can trigger a race between buffer allocation and page mapping to cause a use-after-free condition.

The issue arises when multiple events share one ring buffer via PERF_EVENT_IOC_SET_OUTPUT, and pages mapped as VM_PFNMAP lack refcount protection.

Linux kernel
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 (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 6.12.0-211.47.1.el10_2
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/0cff05bd2186020f8706233e261016d149cc24db
• https://git.kernel.org/stable/c/5948aaf64f81f217a25dcc2bf6c0779bca19566c
• https://git.kernel.org/stable/c/c8b7e113f7b61eef2f017e6329c27c2331058c5a

• Use-after-free in Linux kernel events
• 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