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CVE-2026-46175

f2fs: fix fsck inconsistency caused by FGGC of node block

7.1 EPSS 0.2% AV:L

Published 2026-05-28 (5 months ago) by the Linux kernel CNA. Subsystem fs/f2fs. Debian urgency: not yet assigned.

What to do, per Debian release

Debian's own status for CVE-2026-46175 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source

Release	Status	Version	What this means
Debian 12bookworm	vulnerable	6.1.190-1	No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication.
Debian 13trixie	vulnerable	6.12.113-1	No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication.
Debian 14forky	fixed	7.0.7-1	Update the kernel and reboot. Fixed in 7.0.7-1. A running kernel keeps the old code until the machine restarts.
Debian unstablesid	fixed	7.0.7-1	Update the kernel and reboot. Fixed in 7.0.7-1. A running kernel keeps the old code until the machine restarts.

The vulnerability

What the bug is

During FGGC node block migration, fsck may incorrectly treat the migrated node block as fsync-written data. The reproduction scenario: root@vm:/mnt/f2fs# seq 1 2048 | xargs -n 1 ./test_sync // write inline inode and sync root@vm:/mnt/f2fs# rm -f 1 root@vm:/mnt/f2fs# sync root@vm:/mnt/f2fs# f2fs_io gc_range // move data block in sync mode and not write CP SPO, "fsck --dry-run" find inode has already checkpointed but still with DENT_BIT_SHIFT set The root cause is that GC does not clear the dentry mark and fsync mark during node block migration, leading fsck to misinterpret them as user-issued fsync writes. In BGGC mode, node block migration is handled by f2fs_sync_node_pages(), which guarantees the dentry and fsync marks are cleared before writing. This patch move the set/clear of the fsync|dentry marks into __write_node_folio to make the logic clearer, and ensures the fsync|dentry mark is cleared in FGGC.

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

Debian tracker CVE record NVD kernel CNA record

Signals

Published: 2026-05-28 (5 months ago)source
CVSS: 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:Hsource recompute it
Attack vector: local (AV:L)source
EPSS: 0.17%, higher than 5.8% 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
4.7	6.18.30	8be551f538dc
4.7	7.0.7	e7c6d30169b0
4.7	7.1	c3e238bd1f56

Why the CNA scored it this way

Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source

AV:LAttack vector, local: f2fs is a local block-device filesystem (default on Android/embedded); the vulnerable FGGC path is reached only by a local actor writing to a mounted f2fs volume, not over any network.
AC:LAttack complexity, low: The attacker fully sets up the trigger (write+fsync an inline inode, delete it, exhaust free space to force FGGC of its node block); the corrupt on-disk state then persists until the next checkpoint, and routine power cycles/reboots on the target devices reliably invoke the faulty recovery.
PR:LPrivileges required, low: While the GC ioctls require CAP_SYS_ADMIN, automatic foreground GC (f2fs_balance_fs → f2fs_gc promoting to FG_GC on low free space) runs the exact vulnerable path for any unprivileged user with write access to the filesystem.
UI:NUser interaction, none: Roll-forward recovery runs automatically during the next mount after a crash; no victim action is needed beyond the normal, automatic crash-and-remount cycle.
S:UScope, unchanged: The corruption is confined to the f2fs on-disk structures and the kernel managing them; it does not cross into a different security authority.
C:NConfidentiality impact, none: The bug corrupts filesystem-consistency metadata but provides no read primitive over kernel memory or otherwise-inaccessible data, so there is no information disclosure.
I:HIntegrity impact, high: The migrated node block is misinterpreted as fsynced data, causing incorrect roll-forward recovery that resurrects deleted/stale inode metadata and leaves the on-disk filesystem inconsistent (fsck-detected) — a serious integrity compromise of stored data.
A:HAvailability impact, high: A bad recovery can return an error, aborting the mount and rendering the filesystem/data unavailable until offline fsck (e.g. /data mount failure), and with CONFIG_F2FS_CHECK_FS the recovery error path hits BUG_ON(), crashing the kernel.