CVE-2024-49878 is a vulnerability in the Linux kernel related to the handling of CXL memory resource trees. The issue arises because the resource tree structure causes the region_intersects() function to incorrectly assess System RAM resources when they are descendants of CXL Window resources rather than top-level entries. This leads to incorrect permission checking via /dev/mem, where access is erroneously allowed by devmem_is_allowed(), though later blocked by ioremap(). The flaw can cause misleading error codes and kernel warnings but does not allow unauthorized memory access. The vulnerability has a medium severity score of 5.5.