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CVE-2026-72201
ntfs: validate index entries on reading
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem fs/ntfs. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-72201 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Validate index entries immediately after reading an index root or index block from disk. This eliminates repeated checks in lookup and readdir, and reduce the risk of missing checks in those paths.
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/ntfs/dir.c
fs/ntfs/index.c
fs/ntfs/index.h
fs/ntfs/inode.c
- What this is
- NTFS FILESYSTEMMAINTAINERS section matched on fs/ntfs/ · linux-fsdevel@vger.kernel.org · Maintained
- Kernel module
- ntfs
Check it on the machine
grep -w CONFIG_NTFS_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 ntfsPrints 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 does not build this code in 1 release. It does build it in 2 releases, so the answer depends on which release the machine runs. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookwormn
- trixie?
- forky, sidm
- n
- not enabled on any flavour - this release does not build the code
- ?
- not established - no Makefile entry for the affected file
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switch
- CONFIG_NTFS_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
- 2026-08-15 (2 months ago)source
- CVSS
- 9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.55%, higher than 45.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- fs/ntfs
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 7.1 | 7.1.5 | e2b95d3adb55 |
| 7.1 | 7.2 | 2221b691d7b2 |
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:NAttack vector, network
- Crafted NTFS index entries are parsed when nfsd or ksmbd serves READDIR/LOOKUP on an exported legacy NTFS mount and via local getdents/open/stat; ntfs_readdir, ntfs_lookup_inode_by_name, and ntfs_index_lookup all walk INDX metadata read from disk.
- AC:LAttack complexity, low
- Attackers fully control on-disk INDX/$INDEX_ROOT entry length, key_length, and file_name fields in a malicious image or writable share, so out-of-bounds walks in ntfs_index_next, ntfs_ie_lookup, and ntfs_index_walk_down are reliably triggerable without races or attacker-independent layout.
- PR:NPrivileges required, none
- No victim account or capability is required when a malicious NTFS volume is automounted from USB, dual-boot, or loopback by root/udisks2; unprivileged NFS/SMB clients can also trigger directory walks on exported poisoned mounts without host privileges.
- UI:NUser interaction, none
- Kiosks, desktops, and embedded systems that automount removable NTFS media run ntfs_fill_super and directory index reads on insertion alone; subsequent readdir/lookup walks need no further deliberate victim interaction beyond presenting the volume.
- S:UScope, unchanged
- Impact is kernel heap out-of-bounds access within the host OS parsing context; exploitation yields local privilege escalation, not VM escape, IOMMU bypass, or another cross-authority sandbox boundary.
- C:HConfidentiality impact, high
- Missing per-entry validation lets attacker-controlled key_length and file_name_length drive ntfs_collate, ntfs_ucstonls, and ntfs_index_next past INDX/$INDEX_ROOT buffers, enabling out-of-bounds kernel memory reads and potential pointer disclosure.
- I:HIntegrity impact, high
- Attacker-controlled ie->length and key fields advance index pointers and kmalloc/copy sizes in ntfs_readdir and ntfs_index_lookup, corrupting kmalloc slabs and enabling heap overwrite primitives suitable for kernel code execution.
- A:HAvailability impact, high
- Out-of-bounds index entry walks during mount, readdir, or lookup can fault on unmapped kernel memory and trigger BUG/oops/panic, fully denying system availability even before successful exploitation.