cve 2025 39745

CVE-2025-39745 addresses a spurious RCU torture-test splat in Linux kernels built with the PREEMPT_RT real-time configuration. Microsoft has confirmed that Azure Linux images are potentially affected because they include the open-source library containing the flaw, though this does not guarantee that no other Microsoft product incorporates the same upstream code. The vulnerability is specific to the RCU (Read-Copy-Update) mechanism under real-time preemption, and the fix targets the kernel's torture test harness rather than a general-use exploit path. WindowsForum discussions focus on the technical details of the RCU splat, the PREEMPT_RT context, and the scope of Microsoft's advisory for Azure Linux.