Vulnerability in Linux kernel (CVE-2026-80946)
Summary
Vulnerability in Linux kernel (CVE-2026-80946). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In 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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-80946 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-80946" on the vendor's site.
CVE-2026-80946 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-80946 linux Fixed in: 7.2.6-1
- Ubuntu UBUNTU-CVE-2026-80946 linux-hwe-edge
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com