Use-after-free in Linux kernel - CVE-2026-64300
Published: July 27, 2026
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
Vulnerability details
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.
Affected software
Linux kernel
How to mitigate CVE-2026-64300
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3