CVE-2025-21752: 
Linux Debian vulnerability analysis and mitigation

A vulnerability in the Linux kernel's btrfs filesystem has been identified and assigned CVE-2025-21752. The issue involves the improper use of btrfs_set_item_key_safe() function when modifying keys in the RAID stripe-tree, which can lead to corruption of the tree. This vulnerability was discovered and patched in February 2025 (Kernel Git).

The vulnerability occurs in the btrfs filesystem's RAID stripe-tree handling code. When btrfs_set_item_key_safe() is used to modify keys in the RAID stripe-tree, it can trigger a kernel BUG at fs/btrfs/ctree.c:2602, resulting in an invalid opcode error. The issue manifests when attempting to modify the keys and per-device physical addresses in the RAID stripe-tree, causing tree order corruption that is detected by the checks in btrfs_set_item_key_safe() (Kernel Git).

When triggered, this vulnerability causes a kernel panic due to tree corruption, which can lead to system crashes and potential filesystem inconsistencies. The issue affects systems using the btrfs filesystem with RAID configurations (NVD).

The issue has been fixed by replacing the use of btrfs_set_item_key_safe() with a safer approach using btrfs_duplicate_item() to copy the item and then adjusting both the key and the per-device physical addresses. Users should update to the patched version of the Linux kernel that includes this fix (Kernel Git).