CVE-2026-80857
Received Received - Intake

Use-After-Free in Linux Kernel FUSE Subsystem

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: fuse: wait for FR_FINISHED on abort_on_kill to prevent use-after-free The abort_on_kill path in request_wait_answer() calls fuse_abort_conn() and returns without waiting for FR_FINISHED. If fuse_dev_do_write() is concurrently processing the same request (FR_LOCKED set), the caller frees req->args while it is still being accessed, causing a use-after-free. Fix this by jumping to the existing wait_event(FR_FINISHED) instead of returning early. The wait will not hang because fuse_abort_conn() ensures all requests are ended.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-04
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-80857
EUVD
EUVD-2026-71307

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a use-after-free issue in the FUSE (Filesystem in Userspace) subsystem. When abort_on_kill is triggered, the system fails to wait for FR_FINISHED before freeing memory, allowing concurrent access to freed data.

Detection Guidance

This vulnerability is specific to the Linux kernel's FUSE (Filesystem in Userspace) implementation. Detection requires checking the kernel version and FUSE module behavior. Use commands like 'uname -a' to check kernel version and 'lsmod | grep fuse' to verify FUSE module status. Monitor kernel logs for FUSE-related errors or crashes.

Impact Analysis

This could lead to system crashes, data corruption, or potential privilege escalation if exploited. Systems using FUSE-based filesystems may experience instability or security breaches due to memory corruption.

Mitigation Strategies

Apply the latest kernel update from your distribution to patch this vulnerability. If immediate patching is not possible, consider disabling FUSE if not required by running 'modprobe -r fuse' and blacklisting it. Restrict access to FUSE-based filesystems to trusted users only.

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