Local arbitrary file overwrite via pidfile symlink
Published Aug 28, 2026 · Updated Aug 28, 2026
Link following in Linux intel-speed-select allows local users to overwrite attacker-chosen files through the daemon pidfile. The daemonize function opens a fixed pidfile under /tmp with O_CREAT but without O_NOFOLLOW, then locks and writes through the resulting descriptor. Exploitation requires a local unprivileged user to pre-create the path as a symlink before a root-run daemon starts; the bounded result is an attacker-directed privileged file write.
Summary
What happened
Link following in Linux intel-speed-select allows local users to overwrite attacker-chosen files through the daemon pidfile. The daemonize function opens a fixed pidfile under /tmp with O_CREAT but without O_NOFOLLOW, then locks and writes through the resulting descriptor. Exploitation requires a local unprivileged user to pre-create the path as a symlink before a root-run daemon starts; the bounded result is an attacker-directed privileged file write.
The record
- CVE
- CVE-2026-80663
- Published
- Aug 28, 2026
- Updated
- Aug 28, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1068
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Aug 28, 2026CVE publishedPublication date reported by the CVE source.
- Aug 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=5.18
- Affected versionversion=7fd786dfbd2c55ddee3b87f33c82f1c58bdb1dd6 <19ffeb30fdfce63f8d6aca71bcdddb3f69d46278
- Affected versionversion=7fd786dfbd2c55ddee3b87f33c82f1c58bdb1dd6 <607af438e6430893a822964c841a1994b33acccc
- Affected versionversion=7fd786dfbd2c55ddee3b87f33c82f1c58bdb1dd6 <72a07abc6b9046f07a08bba353cad7667bcc9dce
- Affected versionversion=7fd786dfbd2c55ddee3b87f33c82f1c58bdb1dd6 <905493a6338c82a70da16f86e0a6215db5a3d73d
- Affected versionversion=7fd786dfbd2c55ddee3b87f33c82f1c58bdb1dd6 <db938eb9a3c1317596c28e94413b33426508d51b
- Affected versionversion=7fd786dfbd2c55ddee3b87f33c82f1c58bdb1dd6 <e8adac69d1bdf035ef97cc914e845acd4ef08e28
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Technologies
Your stack
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