CVE-2022-50636
BaseFortify
Publication date: 2025-12-09
Last updated on: 2025-12-09
Assigner: kernel.org
Description
Description
CVSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is in the Linux kernel's handling of PCI devices, specifically related to Virtual Functions (VFs). The function pci_device_is_present() incorrectly returns false for VFs because it checks Vendor and Device IDs, which are 0xffff for VFs, making them appear absent. This causes issues during virtio I/O operations if the driver is unbound or if the number of VFs is set to zero, leading to hung I/O operations and potential system instability. The fix involves checking the Physical Function (PF) instead to correctly detect the presence of VFs.
How can this vulnerability impact me? :
If this vulnerability is triggered, virtio I/O operations may hang when the driver is unbound or when the number of VFs is set to zero. This can cause system processes to stall, potentially leading to degraded system performance or instability, especially in environments relying on virtualized I/O operations.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability may be detected by observing system logs for hung virtio I/O operations or kernel stack traces similar to the provided example, which includes calls like schedule, blk_mq_freeze_queue, virtblk_remove, and virtio_pci_remove. Monitoring for messages indicating that virtio I/O operations hang when unbinding drivers or setting sriov_numvfs to 0 could indicate the presence of this issue. Specific commands to check kernel logs include: 'dmesg | grep virtio' or 'journalctl -k | grep virtio'.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation involves ensuring that virtio I/O operations are not in progress when unbinding the driver or setting sriov_numvfs to 0. Applying the patch that fixes pci_device_is_present() to correctly check the PF instead of relying on Vendor and Device ID for VFs will resolve the issue. Until patched, avoid unbinding drivers or modifying sriov_numvfs while virtio I/O is active to prevent hangs.