System interruption via repeated HFSC cleanup
Published Jul 4, 2025 · Updated Aug 5, 2026
Improper cleanup in the HFSC scheduler in affected Linux kernel versions allows local users to interrupt system availability. hfsc_qlen_notify() repeatedly calls update_vf() after the active count has been reduced and removes an already-removed red-black-tree node without checking or clearing its state. Low-privileged local access is required, and the affected scheduler must traverse a repeated queue-length notification path.
Summary
What happened
Improper cleanup in the HFSC scheduler in affected Linux kernel versions allows local users to interrupt system availability. hfsc_qlen_notify() repeatedly calls update_vf() after the active count has been reduced and removes an already-removed red-black-tree node without checking or clearing its state. Low-privileged local access is required, and the affected scheduler must traverse a repeated queue-length notification path.
The record
- CVE
- CVE-2025-38177
- Published
- Jul 4, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-459, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 4, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.14
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <0475c85426b18eccdcb7f9fb58d8f8e9c6c58c87
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <51eb3b65544c9efd6a1026889ee5fb5aa62da3bb
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <72c61ffbeeb8c50f6d4d70c65d3283aa1bac57a7
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <9030a91235ae4845ec71902c3e0cecfc9ed1f2df
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <9a5fd5c2f4d4afdd5e405083ee53e0789ce76956
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <a5efc95a33bd4fcb879250852828cc58c7862970
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <c1175c4ad01dbc9c979d099861fa90a754f72059
- Affected versionversion=959466588aa7f84ccf79ae36a1d89542eaf9aaec <d06476714d2819b550e0cc39222347e2c8941c9d
What conditions does exploitation require?
What is affected?
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.
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
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Your stack
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