CVE-2026-53017

What the bug is

Data loss can occur when fsync is performed on a newly created file (before any checkpoint has been written) concurrently with a checkpoint operation. The scenario is as follows: create & write & fsync 'file A' write checkpoint - f2fs_do_sync_file // inline inode - f2fs_write_inode // inode folio is dirty - f2fs_write_checkpoint - f2fs_flush_merged_writes - f2fs_sync_node_pages - f2fs_flush_nat_entries - f2fs_fsync_node_pages // no dirty node - f2fs_need_inode_block_update // return false SPO and lost 'file A' f2fs_flush_nat_entries() sets the IS_CHECKPOINTED and HAS_LAST_FSYNC flags for the nat_entry, but this does not mean that the checkpoint has actually completed successfully. However, f2fs_need_inode_block_update() checks these flags and incorrectly assumes that the checkpoint has finished. The root cause is that the semantics of IS_CHECKPOINTED and HAS_LAST_FSYNC are only guaranteed after the checkpoint write fully completes. This patch modifies f2fs_need_inode_block_update() to acquire the sbi->node_write lock before reading the nat_entry flags, ensuring that once IS_CHECKPOINTED and HAS_LAST_FSYNC are observed to be set, the checkpoint operation has already completed.

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/node.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

2026-06-24 (4 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.16%, higher than 4.7% 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
3.8	6.18.57	cb06a07d835b
3.8	7.0.10	20cedb4d9f6b
3.8	7.1	238e14eb7226