CVE-2026-53311

What the bug is

fuse_dentry_revalidate() may be called with a dentry that didn't had ->d_time initialised. The issue was found with KMSAN, where lookup_open() calls __d_alloc(), followed by d_revalidate(), as shown below: ===================================================== BUG: KMSAN: uninit-value in fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 d_revalidate fs/namei.c:1030 [inline] lookup_open fs/namei.c:4405 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x1614/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] Uninit was created at: slab_post_alloc_hook mm/slub.c:4466 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_lru_noprof+0x382/0x1280 mm/slub.c:4807 __d_alloc+0x55/0xa00 fs/dcache.c:1740 d_alloc_parallel+0x99/0x2740 fs/dcache.c:2604 lookup_open fs/namei.c:4398 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x135f/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] =====================================================

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/fuse/dir.c

What this is

FUSE FILESYSTEM [CORE]MAINTAINERS section matched on fs/fuse/ · fuse-devel@lists.linux.dev · Supported

Kernel module

fuse

Check it on the machine

grep -w CONFIG_FUSE_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 fuse

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.

• bookwormm
• trixie, forky, sidy

m

a loadable module on every flavour - check lsmod, can be blacklisted

y

built into the kernel image on every flavour - only a patch removes it

Build switch

CONFIG_FUSE_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

2026-06-26 (4 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.16%, higher than 4.8% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

fs/fuse

Upstream fixes

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

Introduced	Fixed in	Commit
6.16	6.18.34	da3d241c5b92
6.16	7.0.10	3ac9117ba3de
6.16	7.1	5a6baf204610