Local service interruption via timer callback race
Published Dec 16, 2025 · Updated Dec 16, 2025
A timer race in the Linux kernel allows local users to interrupt service by leaving a pending timer with a NULL callback. timer_shutdown_sync() clears timer->function while expiration is still running on another CPU, allowing mod_timer() to leave the timer pending. A low-privileged local user must reach the concurrent timer operations; a later expiration hits the WARN_ON_ONCE check in expire_timers().
Summary
What happened
A timer race in the Linux kernel allows local users to interrupt service by leaving a pending timer with a NULL callback. timer_shutdown_sync() clears timer->function while expiration is still running on another CPU, allowing mod_timer() to leave the timer pending. A low-privileged local user must reach the concurrent timer operations; a later expiration hits the WARN_ON_ONCE check in expire_timers().
The record
- CVE
- CVE-2025-68214
- Published
- Dec 16, 2025
- Updated
- Dec 16, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 16, 2025CVE publishedPublication date reported by the CVE source.
- Dec 16, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0cc04e80458a822300b93f82ed861a513edde194 <176725f4848376530a0f0da9023f956afcc33585
- Affected versionversion=0cc04e80458a822300b93f82ed861a513edde194 <20739af07383e6eb1ec59dcd70b72ebfa9ac362c
- Affected versionversion=0cc04e80458a822300b93f82ed861a513edde194 <6665fbd7730b26d770c232b20d1b907e6a67a914
- Affected versionversion=0cc04e80458a822300b93f82ed861a513edde194 <a01efa7a780c42ac5170a949bd95c9786ffcc60a
- Affected versionversion=334c33aa487be406a149c8b87c38c8399d2dba8d <1a975716cc8977f461e45e28e3e5977d46ad7a6a
- Affected versionversion=6.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo