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CVE-2026-89617
fs/ntfs3: validate dirty page table on log replay
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem fs/ntfs3. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-89617 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Each DIR_PAGE_ENTRY ends in a page_lcns[] array whose length is the on-disk lcns_follow field. check_rstbl() validates the table bookkeeping but never checks that this array fits in the entry, so a crafted lcns_follow lets the v0->v1 conversion memmove and later replay passes run off the entry. Add check_dp_table() to reject, right after check_rstbl(), any entry larger than its size claims via struct_size() (the same expression used to allocate these entries, so the check is overflow-safe by construction). All consumers can then trust lcns_follow as the real capacity. This covers every page_lcns[] access whose index is bounded by the entry itself (the conversion memmove, the HotFix store via find_dp(), and the self-bounded scan loops). Accesses whose index comes from the log record need a separate bound and are handled in a follow-up patch.
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/ntfs3/fslog.c
- What this is
- NTFS3 FILESYSTEMMAINTAINERS section matched on fs/ntfs3/ · ntfs3@lists.linux.dev · Supported
- Kernel module
- ntfs3
Check it on the machine
grep -w CONFIG_NTFS3_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 ntfs3Prints 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 3 releases. It does build it in 2 releases, so the answer depends on which release the machine runs.
- bookwormn
- trixiem
- forky, sidn
- bookworm · linux-6.12m
- n
- not enabled on any flavour - this release does not build the code
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switch
- CONFIG_NTFS3_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
- 2026-09-11 (37 days ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.14%, higher than 2.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- fs/ntfs3
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.15 | 5.15.221 | 0e07ea2fc45a |
| 5.15 | 6.1.188 | 1e90b1703ee1 |
| 5.15 | 6.6.157 | d23155634a4b |
| 5.15 | 6.12.109 | 1200c2779c43 |
| 5.15 | 6.18.50 | 2d94ffc9d7b5 |
| 5.15 | 7.2.4 | 0908da07c23b |
| 5.15 | 7.3 | 006cb7713dec |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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
- log_replay() is reached only from ntfs_fill_super via ntfs_loadlog_and_replay while mounting a local NTFS block device; the dirty-page table is parsed from on-disk $LogFile, not from ksmbd, nfsd, or any received-packet path.
- AC:LAttack complexity, low
- The attacker fully controls DIR_PAGE_ENTRY.lcns_follow and the restart table in a crafted $LogFile, so a value larger than the entry size reliably drives the v0 conversion memmove, HotFix store, and lcns_follow-bounded scan loops off the entry with no race or uncontrollable layout.
- PR:LPrivileges required, low
- Triggering log replay requires mounting the malicious NTFS image (CAP_SYS_ADMIN). Unprivileged users can cause that mount via user+mount namespaces, loop-backed images, or common desktop/Android helpers (udisks/gvfs/USB automount) without init-namespace root.
- UI:NUser interaction, none
- No separate victim action is required: the attacker mounts their own crafted NTFS image (or causes automount of media they supply) and log replay runs automatically in ntfs_fill_super before any further file access.
- S:UScope, unchanged
- Corruption is confined to kernel heap during NTFS journal replay in the same kernel security authority; it is a local privilege-escalation/memory-safety issue, not a VM, IOMMU, or sandbox escape.
- C:HConfidentiality impact, high
- Crafted lcns_follow makes DeleteDirtyClusters, HotFix, and dirty-page scan loops read page_lcns[] far past the kmemdup'd DIR_PAGE_ENTRY, disclosing adjacent kernel heap; that OOB read plus heap corruption yields arbitrary disclosure primitives.
- I:HIntegrity impact, high
- HotFix writes attacker-controlled LCNs and DeleteDirtyClusters zeros page_lcns[j] for j < the forged lcns_follow, overflowing the restart-table heap object into neighboring kmalloc data and enabling arbitrary kernel writes or control-flow hijack.
- A:HAvailability impact, high
- Out-of-bounds heap access during mount-time log replay corrupts slab metadata or adjacent objects, causing kernel oops/panic, and a huge lcns_follow can also hang the mount path in a multi-billion-iteration scan.