System crash via premature policy reference release
Published Nov 12, 2025 · Updated May 11, 2026
A lifecycle flaw in the Linux kernel intel_pstate driver allows attackers to crash a virtualized system during CPU hot removal. update_qos_request() releases its policy reference before freq_qos_update_request() indirectly accesses that policy through the retained QoS request. The path is limited to virtualized environments supporting CPU device hot removal, and triggering it requires control of that operation.
Summary
What happened
A lifecycle flaw in the Linux kernel intel_pstate driver allows attackers to crash a virtualized system during CPU hot removal. update_qos_request() releases its policy reference before freq_qos_update_request() indirectly accesses that policy through the retained QoS request. The path is limited to virtualized environments supporting CPU device hot removal, and triggering it requires control of that operation.
The record
- CVE
- CVE-2025-40194
- Published
- Nov 12, 2025
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Nov 12, 2025CVE publishedPublication date reported by the CVE source.
- May 11, 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=5.4
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <0a58d3e77b22b087a57831c87cafd360e144a5bd
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <15ac9579ebdaf22a37d7f60b3a8efc1029732ef9
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <57e4a6aadf12578b96a038373cffd54b3a58b092
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <69a18ff6c60e8e113420f15355fad862cb45d38e
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <69e5d50fcf4093fb3f9f41c4f931f12c2ca8c467
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <ad4e8f9bdbef11a19b7cb93e7f313bf59bdcc3b4
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <ba63d4e9857a72a89e71a4eff9f2cc8c283e94c3
- Affected versionversion=da5c504c7aae96db68c4b38e2564a88e91842d89 <bc26564bcc659beb6d977cd6eb394041ec2f2851
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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