CVE-2026-80663: tools/power/x86/intel-speed-select: Harden daemon pidfile open
In the Linux kernel, the following vulnerability has been resolved:
tools/power/x86/intel-speed-select: Harden daemon pidfile open
Avoid symlink-based pidfile clobbering by opening the pidfile with ONOFOLLOW and validating it with fstat() before locking/writing.
The daemon currently uses a fixed pidfile path under /tmp. A local unprivileged user can pre-create a symlink at that path and cause a root-run daemon instance to write into an attacker-chosen file.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Harden the intel-speed-select daemon’s pidfile handling: open the fixed pidfile path under /tmp using O_NOFOLLOW and call fstat() to validate the file before locking and writing, to prevent symlink-based pidfile clobbering.
tools/power/x86/intel-speed-select daemon pidfile open flags and validation = Open pidfile with O_NOFOLLOW and validate with fstat() before locking/writing
Event History
Frequently Asked Questions
Who can exploit this issue?
A local unprivileged user who can create a symlink at the daemon's fixed pidfile path under /tmp can exploit the issue when the daemon is run as root.
What must occur for the symlink to cause an attacker-chosen file to be written?
The attacker must pre-create the symlink before a root-run daemon instance opens and writes its pidfile. The vulnerable behavior is tied to the daemon's use of a fixed pidfile location under /tmp.
How is the resolved implementation protected?
The resolved implementation opens the pidfile with O_NOFOLLOW and validates it with fstat() before locking or writing it, preventing symlink-based pidfile clobbering.