fuse: copy request headers via a stack buffer for io-uring

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80946
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:19:00 UTC
Updated2026-09-11 20:19:00 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: fuse: copy request headers via a stack buffer for io-uring The fuse-io-uring transport copies req->in.h out to the ring in fuse_uring_copy_to_ring() and req->out.h back in fuse_uring_commit(). Both headers live inside the fuse_request slab object, whose cache (fuse_req_cachep) is created without a usercopy whitelist, so copying them directly to/from userspace trips CONFIG_HARDENED_USERCOPY and panics: usercopy: Kernel memory exposure attempt detected from SLUB object 'fuse_request' (offset 56, size 40)! kernel BUG at mm/usercopy.c:102! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:usercopy_abort (mm/usercopy.c:90) Call Trace: __check_heap_object (mm/slub.c:8268) __check_object_size (mm/usercopy.c:197 mm/usercopy.c:258 mm/usercopy.c:223) copy_header_to_ring (fs/fuse/dev_uring.c:618) fuse_uring_prepare_send (fs/fuse/dev_uring.c:776 fs/fuse/dev_uring.c:785) fuse_uring_send_in_task (fs/fuse/dev_uring.c:1306) tctx_task_work_run (io_uring/tw.c:96) task_work_run (kernel/task_work.c:233) io_run_task_work (io_uring/tw.h:84) io_cqring_wait (io_uring/wait.c:278) __do_sys_io_uring_enter (io_uring/io_uring.c:2685) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Bounce both headers through an on-stack copy so the usercopy touches stack memory, not the slab object.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected c090c8abae4b6b77a1bee116aa6c385456ebef96 194d0fb0ea4720535ff3168c9d04c7632cec7071 git Not specified
CNA Linux Linux affected c090c8abae4b6b77a1bee116aa6c385456ebef96 a47a416ff68d706dc3327ab583f86b9ee757358b git Not specified
CNA Linux Linux affected c090c8abae4b6b77a1bee116aa6c385456ebef96 fd10f40af314f07b6d6e028b1ca25c8b49903aab git Not specified
CNA Linux Linux affected 6.14 Not specified
CNA Linux Linux unaffected 6.14 semver Not specified
CNA Linux Linux unaffected 6.18.51 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/fd10f40af314f07b6d6e028b1ca25c8b49903aab 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/194d0fb0ea4720535ff3168c9d04c7632cec7071 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a47a416ff68d706dc3327ab583f86b9ee757358b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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