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CVE-2026-64260
fuse-uring: Avoid queue->stopped races and set/read that value under lock
Published 2026-07-25 (3 months ago) by the Linux kernel CNA. Subsystem fs/fuse. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-64260 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 | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
There are several readers of queue->stopped that check the value under lock, but fuse_uring_commit_fetch() did not and actually the value was not set under the lock in fuse_uring_abort_end_requests() either. Especially in fuse_uring_commit_fetch it is important to check under a lock, because due to races 'struct fuse_req' might be freed with fuse_request_end, but another thread/cpu might already do teardown work.
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/dev_uring.c
- What this is
- FUSE FILESYSTEM [IO-URING]MAINTAINERS section matched on fs/fuse/dev_uring.c · fuse-devel@lists.linux.dev · Maintained
Check it on the machine
grep -wE 'CONFIG_FUSE_FS|CONFIG_FUSE_IO_URING' /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.
Show whether Debian builds this, per release
Debian builds this code. Every release with an answer below compiles the affected file into the kernels it ships. The build rule could not be established for 2 releases, so nothing is claimed about those.
- bookworm, trixie?
- forky, sidy
- ?
- not established - no Makefile entry for the affected file
- y
- built into the kernel image on every flavour - only a patch removes it
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 switches
- CONFIG_FUSE_FS, CONFIG_FUSE_IO_URING
- Reads as
- all on means the file is compiled; any one off means it is not.
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
- 2026-07-25 (3 months 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
- 0.13%, higher than 2.2% 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 |
|---|---|---|
| 6.14 | 6.18.39 | 39c8e925b207 |
| 6.14 | 7.1.4 | 4021a3a79eee |
| 6.14 | 7.2 | b70a3aca1693 |
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
- The flaw is reached locally by submitting IORING_OP_URING_CMD/FUSE_IO_URING_CMD_COMMIT_AND_FETCH operations on an attached /dev/fuse descriptor.
- AC:LAttack complexity, low
- Once FUSE-over-io-uring is enabled, the attacker controls both race participants by issuing commit SQEs while concurrently aborting or unmounting the connection.
- PR:LPrivileges required, low
- An ordinary user can create a FUSE mount through FS_USERNS_MOUNT and user namespaces, submit commands through /dev/fuse, and access the user-owned fusectl abort control without init-namespace capabilities.
- UI:NUser interaction, none
- The attacker can create the mount, generate FUSE requests, submit commits, and trigger teardown without another user's participation.
- S:UScope, unchanged
- This is a standard local kernel privilege-escalation condition within the kernel's security authority, not a guest-to-host or IOMMU boundary escape.
- C:HConfidentiality impact, high
- The race causes a fuse_req use-after-free and double-end with stale list, pointer, and refcount accesses, which can be leveraged to disclose arbitrary kernel memory.
- I:HIntegrity impact, high
- Teardown writes through stale list pointers, flags, error fields, and refcounts and can corrupt or double-free a reallocated fuse_req, enabling arbitrary kernel writes or control-flow hijacking.
- A:HAvailability impact, high
- The use-after-free, list corruption, and double-ending of requests can cause an oops, panic, deadlock, or complete system compromise.