CVE-2024-39508

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A concurrency issue exists in the io uring/io-wq component of the Linux kernel. The io worker->flags structure can be accessed through multiple data paths, leading to data races—where different tasks on different CPUs read and write to the same memory location simultaneously. This issue was identified using KCSAN (Kernel Concurrency Sanitizer), a tool used to detect data races in the kernel. The race condition occurs specifically within the io worker handle work() and io wq activate free worker() functions. Exploitation of this synchronization error in the create io worker() function may allow an attacker to cause a denial of service.

Recommendations Refactor the code to use atomic operations set bit(), test bit(), and clear bit() instead of basic logical AND/OR operations when manipulating worker->flags to ensure thread-safe access. As a temporary mitigation, restrict the use of the create io worker() function if possible until the update is applied.