CVE-2025-40137

What the bug is

syzbot reports a bug as below: loop0: detected capacity change from 0 to 40427 F2FS-fs (loop0): Wrong SSA boundary, start(3584) end(4096) blocks(3072) F2FS-fs (loop0): Can't find valid F2FS filesystem in 1th superblock F2FS-fs (loop0): invalid crc value F2FS-fs (loop0): f2fs_convert_inline_folio: corrupted inline inode ino=3, i_addr[0]:0x1601, run fsck to fix. ------------[ cut here ]------------ kernel BUG at fs/inode.c:753! RIP: 0010:clear_inode+0x169/0x190 fs/inode.c:753 Call Trace: <TASK> evict+0x504/0x9c0 fs/inode.c:810 f2fs_fill_super+0x5612/0x6fa0 fs/f2fs/super.c:5047 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692 vfs_get_tree+0x8f/0x2b0 fs/super.c:1815 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808 do_mount fs/namespace.c:4136 [inline] __do_sys_mount fs/namespace.c:4347 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4324 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f During f2fs_evict_inode(), clear_inode() detects that we missed to truncate all page cache before destorying inode, that is because in below path, we will create page #0 in cache, but missed to drop it in error path, let's fix it. - evict - f2fs_evict_inode - f2fs_truncate - f2fs_convert_inline_inode - f2fs_grab_cache_folio : create page #0 in cache - f2fs_convert_inline_folio : sanity check failed, return -EFSCORRUPTED - clear_inode detects that inode->i_data.nrpages is not zero

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

fs/f2fs/file.c

What this is

F2FS FILE SYSTEMMAINTAINERS section matched on fs/f2fs/ · linux-f2fs-devel@lists.sourceforge.net · Maintained

Kernel module

f2fs

Check it on the machine

grep -w CONFIG_F2FS_FS /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w f2fs

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookworm, trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64

M

a module where it is built at all; some flavours do not build it

Build switch

CONFIG_F2FS_FS

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2025-11-12 (11 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.9% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

fs/f2fs

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
3.19	6.6.112	83a8e4efea02
3.19	6.12.53	a7b7ebdd7045
3.19	6.17.3	3b0c8908faa1
3.19	6.18	9251a9e6e871