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CVE-2026-89832
f2fs: fix to clear dirty flag on folio in error path
Published 2026-09-16 (33 days ago) by the Linux kernel CNA. Subsystem fs/f2fs. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-89832 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-6568-1 · 2026-10-16 · text | 6.12.113-1 | Update the kernel and reboot. DSA-6568-1 shipped the fix on 2026-10-16, in 6.12.113-1. 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. |
The vulnerability
What the bug is
If node block is corrupted due to chksum mismatch or inconsistent footer info, it needs to drop clear flag of node folio, in order to persist inconsistent node data to storage.
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/f2fs/node.c
- What this is
- F2FS FILE SYSTEMMAINTAINERS section matched on fs/f2fs/ · linux-f2fs-devel@lists.sourceforge.net · Maintained
- Kernel module
- f2fs
Check it on the machine
grep -w CONFIG_F2FS_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 f2fsPrints 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, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookworm, trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_F2FS_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
- 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
- 0.18%, higher than 6.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- fs/f2fs
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.2 | 6.12.112 | 34732e3a8713 |
| 5.2 | 6.18.51 | ab35ae07f2b5 |
| 5.2 | 7.2.5 | 3923ec2b98c9 |
| 5.2 | 7.3 | 5b86eab84ac8 |
| 4.19.51 | 0 | 0 |
| 5.1.10 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DSA-6568-1 | 2026-10-16 | trixie 6.12.113-1 | 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
- __get_node_folio is reached only through local VFS operations (lookup, open, read/write, fallocate, fsync, GC) on a mounted f2fs volume such as Android userdata or removable flash; it is not a ksmbd/nfsd/packet-processing path.
- AC:LAttack complexity, low
- A crafted f2fs image lets the attacker pick node footers and nids so a dirty direct-node folio is later re-fetched as NODE_TYPE_INODE (or fails checksum) on ordinary file ops; triggering is deterministic with no race or rare config.
- PR:LPrivileges required, low
- After automount (Android vold/udisks2 portable f2fs) or on already-mounted userdata, any unprivileged user with file access reaches __get_node_folio via write then lookup; no CAP_SYS_ADMIN is needed on that syscall path.
- UI:NUser interaction, none
- The attacker dirties the node and then looks up the type-confused nid themselves; removable f2fs is commonly auto-mounted and scanned without a separate victim mount or open step.
- S:UScope, unchanged
- Dirty-flag mishandling, persisted node metadata, and any page-cache fallout remain in the host kernel's authority; this is not a VM escape, container breakout, or IOMMU bypass.
- C:HConfidentiality impact, high
- A still-dirty corrupted node folio can be written back with inconsistent mappings, and a later read_node_folio will read into that dirty folio; file offsets can then resolve to other files' or leftover blocks and disclose their contents.
- I:HIntegrity impact, high
- Writeback of the leftover dirty node persists inconsistent footer/checksum metadata, and the subsequent read into a dirty folio overwrites in-memory node contents from disk, corrupting block maps in an attacker-influenced way.
- A:HAvailability impact, high
- Footer failure on a still-dirty node stops checkpoint (and panics with errors=panic), can leak F2FS_DIRTY_NODES so checkpoint retries hang, and dirty !uptodate node folios can oops or freeze filesystem I/O.