Linux Kernel erofs UAF via filebacked mounts with directio
CVE-2026-23224 Published on February 18, 2026
erofs: fix UAF issue for file-backed mounts w/ directio option
In the Linux kernel, the following vulnerability has been resolved:
erofs: fix UAF issue for file-backed mounts w/ directio option
[ 9.269940][ T3222] Call trace:
[ 9.269948][ T3222] ext4_file_read_iter+0xac/0x108
[ 9.269979][ T3222] vfs_iocb_iter_read+0xac/0x198
[ 9.269993][ T3222] erofs_fileio_rq_submit+0x12c/0x180
[ 9.270008][ T3222] erofs_fileio_submit_bio+0x14/0x24
[ 9.270030][ T3222] z_erofs_runqueue+0x834/0x8ac
[ 9.270054][ T3222] z_erofs_read_folio+0x120/0x220
[ 9.270083][ T3222] filemap_read_folio+0x60/0x120
[ 9.270102][ T3222] filemap_fault+0xcac/0x1060
[ 9.270119][ T3222] do_pte_missing+0x2d8/0x1554
[ 9.270131][ T3222] handle_mm_fault+0x5ec/0x70c
[ 9.270142][ T3222] do_page_fault+0x178/0x88c
[ 9.270167][ T3222] do_translation_fault+0x38/0x54
[ 9.270183][ T3222] do_mem_abort+0x54/0xac
[ 9.270208][ T3222] el0_da+0x44/0x7c
[ 9.270227][ T3222] el0t_64_sync_handler+0x5c/0xf4
[ 9.270253][ T3222] el0t_64_sync+0x1bc/0x1c0
EROFS may encounter above panic when enabling file-backed mount w/
directio mount option, the root cause is it may suffer UAF in below
race condition:
- z_erofs_read_folio wq s_dio_done_wq
- z_erofs_runqueue
- erofs_fileio_submit_bio
- erofs_fileio_rq_submit
- vfs_iocb_iter_read
- ext4_file_read_iter
- ext4_dio_read_iter
- iomap_dio_rw
: bio was submitted and return -EIOCBQUEUED
- dio_aio_complete_work
- dio_complete
- dio->iocb->ki_complete (erofs_fileio_ki_complete())
- kfree(rq)
: it frees iocb, iocb.ki_filp can be UAF in file_accessed().
- file_accessed
: access NULL file point
Introduce a reference count in struct erofs_fileio_rq, and initialize it
as two, both erofs_fileio_ki_complete() and erofs_fileio_rq_submit() will
decrease reference count, the last one decreasing the reference count
to zero will free rq.
Products Associated with CVE-2026-23224
You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-23224 are published in Linux Kernel:
Affected Versions
Linux:- Version fb176750266a3d7f42ebdcf28e8ba40350b27847 and below ae385826840a3c8e09bf38cac90adcd690716f57 is affected.
- Version fb176750266a3d7f42ebdcf28e8ba40350b27847 and below d741534302f71c511eb0bb670b92eaa7df4a0aec is affected.
- Version fb176750266a3d7f42ebdcf28e8ba40350b27847 and below b2ee5e4d5446babd23ff7beb4e636be0fb3ea5aa is affected.
- Version fb176750266a3d7f42ebdcf28e8ba40350b27847 and below 1caf50ce4af096d0280d59a31abdd85703cd995c is affected.
- Version 6.12 is affected.
- Before 6.12 is unaffected.
- Version 6.12.72, <= 6.12.* is unaffected.
- Version 6.18.11, <= 6.18.* is unaffected.
- Version 6.19.1, <= 6.19.* is unaffected.
- Version 7.0-rc1, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.