cve 2025 40272

CVE-2025-40272 is a use-after-free race condition in the Linux kernel's secret memory subsystem, specifically in the memfd_secret fault path. The vulnerability affects page-fault handling for memory regions created by memfd_secret(2) and can cause a kernel oops when two tasks fault the same page concurrently. The fix reorders fault-handler cleanup to restore the direct map before freeing the allocated folio. This issue is particularly sensitive because it impacts kernel mechanisms designed to protect in-memory secrets. The tag covers discussions and analysis of this CVE, including the upstream patch and its implications for system stability and security.