Use-After-Free Vulnerability in B2C2 FlexCop PCI Device by Linux Kernel

CVE-2025-39996

What is CVE-2025-39996?

A use-after-free vulnerability exists in the Linux kernel related to the handling of the B2C2 FlexCop PCI device. The issue arises in the flexcop_pci_remove() function, which calls cancel_delayed_work() without ensuring that any delayed work items, such as irq_check_work, have completed. This can lead to a scenario where memory is freed while still in use, potentially allowing unauthorized access or manipulation of kernel memory by the executing callback. The flaw was identified through static analysis and can be reproduced under specific conditions, including introducing artificial delays in the delayed work callback.

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