CVE-2026-64265
Received Received - Intake

Use-After-Free in Linux Kernel FUSE Subsystem

Publication date: 2026-07-25

Last updated on: 2026-07-25

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: fuse: clear intr_entry in fuse_resend and fuse_remove_pending_req When fuse_resend() moves a request from fpq->processing back to fiq->pending, it sets FR_PENDING and clears FR_SENT but does not remove the requests intr_entry from fiq->interrupts. If the request had FR_INTERRUPTED set from a prior signal, intr_entry remains dangling on fiq->interrupts. When the requesting task then receives a fatal signal, fuse_remove_pending_req() sees FR_PENDING=1, removes the request from fiq->pending and frees it via the refcount path, also without cleaning intr_entry. The stale intr_entry causes use-after-free when fuse_read_interrupt() iterates fiq->interrupts: - list_del_init(&req->intr_entry) -> UAF write on freed slab - req->in.h.unique -> UAF read, data leaked to userspace Remove intr_entry from fiq->interrupts in fuse_resend() for interrupted requests before they are placed back on fiq->pending. Add a WARN_ON if the intr_entry is not empty on request destruction.

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Meta Information

Published
2026-07-25
Last Modified
2026-07-25
Generated
2026-07-25
AI Q&A
2026-07-25
EPSS Evaluated
N/A
NVD
CVE-2026-64265
EUVD
EUVD-2026-48977

Affected Vendors & Products

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

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a use-after-free vulnerability in the Linux kernel's FUSE (Filesystem in Userspace) component. It occurs when a request is moved between processing and pending queues without properly clearing interrupt-related data. This leaves a dangling pointer that can be accessed after the memory is freed, leading to potential data leaks or crashes.

Detection Guidance

This vulnerability is specific to the Linux kernel's FUSE (Filesystem in Userspace) implementation. Detection requires checking kernel logs for use-after-free errors related to FUSE operations or examining kernel memory corruption patterns. No direct network detection commands are applicable. Review kernel logs with dmesg or journalctl for FUSE-related errors.

Impact Analysis

If exploited, this could allow an attacker to cause system crashes, leak sensitive data from kernel memory, or potentially escalate privileges. Users running systems with vulnerable kernel versions could experience instability or security breaches.

Mitigation Strategies

Apply the latest kernel update that includes the fix for this CVE. If immediate patching is not possible, consider disabling FUSE functionality temporarily or restricting access to FUSE-based filesystems until the patch is applied. Monitor kernel logs for signs of exploitation attempts.

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