CVE-2026-93268

What the bug is

ext4_try_to_expand_extra_isize() is called from __ext4_mark_inode_dirty() while holding an active jbd2 handle. During mount (!SB_ACTIVE), the expand path may move xattrs to external blocks and release ea_inodes via iput(). When !SB_ACTIVE, iput() calls write_inode_now() which acquires s_writepages_rwsem, creating a circular lock dependency: s_writepages_rwsem --> jbd2_handle --> xattr_sem --> s_writepages_rwsem This can be triggered via: ext4_process_orphan() -> ext4_truncate() -> ext4_mark_inode_dirty() -> ext4_try_to_expand_extra_isize() or: ext4_evict_inode() -> ext4_mark_inode_dirty() -> ext4_try_to_expand_extra_isize() Skip expansion when !SB_ACTIVE. This is a minor loss of functionality (extra isize won't grow for these inodes during mount), which e2fsck can resolve later if needed.

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/ext4/inode.c

What this is

EXT4 FILE SYSTEMMAINTAINERS section matched on fs/ext4/ · linux-ext4@vger.kernel.org · Maintained

Kernel module

ext4

Check it on the machine

grep -w CONFIG_EXT4_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 ext4

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 code. Every release below compiles the affected file into the kernels it ships.

• bookworm, trixie, forky, sid, bookworm · linux-6.12b

b

built in on some flavours, a module on others

Build switch

CONFIG_EXT4_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

2026-09-24 (24 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.20%, higher than 8.7% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

fs/ext4

Upstream fixes

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

Introduced	Fixed in	Commit
4.7	5.10.270	41897f1bcf4a
4.7	5.15.221	9c3469377b1d
4.7	6.1.188	1dd4882dbdc8
4.7	6.6.157	7ba09330d9ea
4.7	6.12.110	c5e6434cc55f
4.7	6.18.52	7ace189b9ea7
4.7	7.2.6	2fb8ff81659a
4.7	7.3	7461c60b9c6a

Debian advisories