Service interruption via exclusive INTx disable-depth race
Published Apr 5, 2024 · Updated May 12, 2026
Race condition in Linux kernel VFIO/PCI allows local users to leave an exclusive INTx interrupt permanently disabled on affected systems. The exclusive-INTx setup enables the IRQ in request_irq() before reconciling the masked flag, so an intervening interrupt increments the disable depth twice. Exploitation requires a passthrough device without DisINTx support that needs irqchip masking; the resulting masked state prevents the user from re-enabling that interrupt.
Summary
What happened
Race condition in Linux kernel VFIO/PCI allows local users to leave an exclusive INTx interrupt permanently disabled on affected systems. The exclusive-INTx setup enables the IRQ in request_irq() before reconciling the masked flag, so an intervening interrupt increments the disable depth twice. Exploitation requires a passthrough device without DisINTx support that needs irqchip masking; the resulting masked state prevents the user from re-enabling that interrupt.
The record
- CVE
- CVE-2024-27437
- Published
- Apr 5, 2024
- Updated
- May 12, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-20, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 5, 2024CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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- Affected versionversion=0 <*
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
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Your stack
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