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CVE-2026-90048
fs/ntfs3: fix slab-out-of-bounds write in ni_create_attr_list()
Published 2026-09-16 (33 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-2026-90048 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 | 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
ni_create_attr_list() allocates a fixed buffer of al_aligned(record_size) (== record_size) bytes and then walks every attribute of the primary MFT record, writing one ATTR_LIST_ENTRY per attribute and advancing the cursor by le_size(name_len), with no check against the end of the buffer; the total size is only computed after the loop. A minimum-size resident attribute occupies SIZEOF_RESIDENT (0x18 = 24) bytes on disk, but an unnamed attribute expands to le_size(0) (0x20 = 32) bytes in the list. Because the number of attributes in a record is not bounded (mi_enum_attr() accepts arbitrarily many equal-type, nameless minimum-size attributes), a crafted record packed with such attributes produces a list larger than record_size and overflows the heap buffer. This is reachable from a crafted, loop-mounted NTFS image: opening the file and adding an attribute (e.g. via setxattr) drives ntfs_set_ea() -> ni_insert_resident() -> ni_insert_attr() -> ni_ins_attr_ext() -> ni_create_attr_list(). BUG: KASAN: slab-out-of-bounds in ni_create_attr_list+0xc48/0x1058 Write of size 4 at addr ffff000008984c00 by task setfattr/345 ni_create_attr_list+0xc48/0x1058 ni_ins_attr_ext+0x510/0x7c0 ni_insert_attr+0x3f8/0x70c ni_insert_resident+0xc8/0x3b0 ntfs_set_ea+0x66c/0xd28 ntfs_setxattr+0x4d8/0x5b0 __arm64_sys_setxattr+0xa4/0x124 Allocated by task 345: ni_create_attr_list+0x188/0x1058 The buggy address belongs to the cache kmalloc-1k of size 1024 (the write lands at object+1024). Size the buffer from the actual attributes instead of assuming a single record_size is always enough.
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/frecord.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
- 2026-09-16 (33 days 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
- 0.67%, higher than 51.1% 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 | 6.6.157 | 7e9aee7e4d97 |
| 5.15 | 6.12.110 | fa2215cf4514 |
| 5.15 | 6.18.51 | d07e281f2a77 |
| 5.15 | 7.2.5 | a84f3db72561 |
| 5.15 | 7.3 | 7c4841e2a627 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| 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:NAttack vector, network
- ntfs3 registers export_operations, so ksmbd/nfsd VFS write and setxattr on an exported NTFS volume reach ni_create_attr_list() via ntfs_set_size/attr_set_size_ex and ntfs_setxattr→ni_insert_resident→ni_ins_attr_ext; NAS/router SMB sharing of USB NTFS is a reasonable high-impact path.
- AC:LAttack complexity, low
- The attacker fully controls a primary MFT record packed with unnamed SIZEOF_RESIDENT attributes, so the ATTR_LIST_ENTRY walk overflows the fixed kzalloc(record_size) buffer on the first attribute insert or allocation extend; no race or attacker-uncontrollable layout is required.
- PR:NPrivileges required, none
- Triggering needs only write or setxattr permission on the crafted file, including guest/anonymous SMB or a permissive NFS export; no local account, init-namespace root, or CAP_SYS_ADMIN is required on the trigger path.
- UI:NUser interaction, none
- Once the crafted NTFS volume is mounted and exported, or automounted from removable/shared storage, the attacker triggers the overflow with an ordinary write, truncate, or setxattr; no extra victim clicks, prompts, or confirmation are required.
- S:UScope, unchanged
- The slab out-of-bounds write corrupts kernel heap in the same host OS security authority as ntfs3; it can enable privilege escalation but does not cross a VM, IOMMU, or sandbox boundary.
- C:HConfidentiality impact, high
- The overflow writes attacker-controlled ATTR_LIST_ENTRY fields (type, name, id) past the kmalloc-1k object into adjacent slab, a heap-corruption primitive that can be leveraged for kernel memory disclosure.
- I:HIntegrity impact, high
- The unbounded ATTR_LIST_ENTRY walk is a slab out-of-bounds write of attacker-influenced attribute metadata into adjacent heap objects, enabling arbitrary kernel writes and potential control-flow hijack.
- A:HAvailability impact, high
- KASAN reports a slab-out-of-bounds write in ni_create_attr_list(); overflowing the kmalloc object corrupts adjacent heap and causes a kernel oops, panic, or hang.