Skip to content
CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-31715

f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io()

Read JSON ↗CVE.org ↗
Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io() The xfstests case "generic/107" and syzbot have both reported a NULL pointer dereference. The concurrent scenario that triggers the panic is as follows: F2FS_WB_CP_DATA write callback umount - f2fs_write_checkpoint - f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA) - blk_mq_end_request - bio_endio - f2fs_write_end_io : dec_page_count(sbi, F2FS_WB_CP_DATA) : wake_up(&sbi->cp_wait) - kill_f2fs_super - kill_block_super - f2fs_put_super : iput(sbi->node_inode) : sbi->node_inode = NULL : f2fs_in_warm_node_list - is_node_folio // sbi->node_inode is NULL and panic The root cause is that f2fs_put_super() calls iput(sbi->node_inode) and sets sbi->node_inode to NULL after sbi->nr_pages[F2FS_WB_CP_DATA] is decremented to zero. As a result, f2fs_in_warm_node_list() may dereference a NULL node_inode when checking whether a folio belongs to the node inode, leading to a panic. This patch fixes the issue by calling f2fs_in_warm_node_list() before decrementing sbi->nr_pages[F2FS_WB_CP_DATA], thus preventing the use-after-free condition.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < 7dbdab4430e4654db9aacef12b9b3b8b29ca25cbaffected
  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < ffb94770dbdfb5411be5d9f44a960b010ec890adaffected
  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < 0d40b26377f891e6dcb6efaf8ef9374c99be1b1daffected
  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < 1171f329cf1c175321251ac40fd126150d7ad1e8affected
  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < 7be222de96c0f9eee6e65eeb017ef855ee185cfaaffected
  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < 963d2e24d9d92a31e6773b0f642214f10013ebf7affected
  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < 188bb65f247a7a7c62f287c9a263aee3cad96fa5affected
  • 50fa53eccf9f911a5b435248a2b0bd484fd82e5e to < 2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53affected

Linux Linux

Default version status: affected

  • 4.19affected
  • 0 to < 4.19unaffected
  • 5.10.259 to ≤ 5.10.*unaffected
  • 5.15.210 to ≤ 5.15.*unaffected
  • 6.1.176 to ≤ 6.1.*unaffected
  • 6.6.140 to ≤ 6.6.*unaffected
  • 6.12.86 to ≤ 6.12.*unaffected
  • 6.18.25 to ≤ 6.18.*unaffected
  • 7.0.2 to ≤ 7.0.*unaffected
  • 7.1 to ≤ *unaffected

References