Linux Kernel up to 6.18.50/7.2.3 FUSE fs/fuse/dev_uring.c fuse_uring_copy_to_ring stack-based overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.0$0-$5k0.00+

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.18.50/7.2.3. This affects the function fuse_uring_copy_to_ring of the file fs/fuse/dev_uring.c of the component FUSE. Executing a manipulation can lead to stack-based overflow. This vulnerability is tracked as CVE-2026-80946. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.18.50/7.2.3. This vulnerability affects the function fuse_uring_copy_to_ring of the file fs/fuse/dev_uring.c of the component FUSE. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-80946 since 08/26/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/11/2026).

Upgrading to version 6.18.51, 7.2.4 or 7.3-rc1 eliminates this vulnerability. Applying the patch 194d0fb0ea4720535ff3168c9d04c7632cec7071/a47a416ff68d706dc3327ab583f86b9ee757358b/fd10f40af314f07b6d6e028b1ca25c8b49903aab is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.51/7.2.4/7.3-rc1
Patch: 194d0fb0ea4720535ff3168c9d04c7632cec7071/a47a416ff68d706dc3327ab583f86b9ee757358b/fd10f40af314f07b6d6e028b1ca25c8b49903aab

Timelineinfo

08/26/2026 CVE reserved
09/11/2026 +16 days Advisory disclosed
09/11/2026 +0 days VulDB entry created
09/11/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-80946 (🔒)
GCVE (CVE): GCVE-0-2026-80946
GCVE (VulDB): GCVE-100-402652

Entryinfo

Created: 09/11/2026 23:21
Changes: 09/11/2026 23:21 (60)
Complete: 🔍
Cache ID: 216::103

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