CVE-2026-63816

Summary

In the Linux kernel, the following vulnerability has been resolved:

f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode

  • ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE) - shrink
  • f2fs_gc
  • gc_data_segment
  • ra_data_block(cow_inode) - mapping = F2FS_I(inode)->atomic_inode->i_mapping : f2fs_is_cow_file(cow_inode) is true - f2fs_evict_inode(atomic_inode) - clear_inode_flag(fi->cow_inode, FI_COW_FILE) - F2FS_I(fi->cow_inode)->atomic_inode = NULL … - truncate_inode_pages_final(atomic_inode) - f2fs_grab_cache_folio(mapping) : create folio in atomic_inode->mapping - clear_inode(atomic_inode) - BUG_ON(atomic_inode->i_data.nrpages)

We need to add a reference on fi->atomic_inode before using its mapping field during garbage collection, otherwise, it will cause UAF issue.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux3db1de0e582c358dd013f3703cd55b5fe4076436 < 56038756aae68312df00d4aa1d97e51ef3aca725affected
LinuxLinux3db1de0e582c358dd013f3703cd55b5fe4076436 < a499f77c06050a28c897bdbd86cd2f0721ae0743affected
LinuxLinux3db1de0e582c358dd013f3703cd55b5fe4076436 < a805fec35c201c59643ddcde713bce4051c8ee27affected
LinuxLinux3db1de0e582c358dd013f3703cd55b5fe4076436 < e0288584baa5dc41df4a829a023c4c1b33fe53d7affected
LinuxLinux6db52f1944417c2601182a591a704e2f119c5215affected
LinuxLinux5.18.18 < 5.19affected
LinuxLinux5.19affected
LinuxLinux0 < 5.19unaffected
LinuxLinux6.12.96 <= 6.12.*unaffected
LinuxLinux6.18.39 <= 6.18.*unaffected
LinuxLinux7.1.3 <= 7.1.*unaffected
LinuxLinux7.2-rc1 <= *unaffected

Weaknesses

References