CVE-2026-53311

Analyzed Analyzed - Analysis Complete

Uninitialized Memory Exposure in Linux Kernel FUSE

Publication date: 2026-06-26

Last updated on: 2026-07-06

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: fuse: fix uninit-value in fuse_dentry_revalidate() fuse_dentry_revalidate() may be called with a dentry that didn't had ->d_time initialised. The issue was found with KMSAN, where lookup_open() calls __d_alloc(), followed by d_revalidate(), as shown below: ===================================================== BUG: KMSAN: uninit-value in fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 d_revalidate fs/namei.c:1030 [inline] lookup_open fs/namei.c:4405 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x1614/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] Uninit was created at: slab_post_alloc_hook mm/slub.c:4466 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_lru_noprof+0x382/0x1280 mm/slub.c:4807 __d_alloc+0x55/0xa00 fs/dcache.c:1740 d_alloc_parallel+0x99/0x2740 fs/dcache.c:2604 lookup_open fs/namei.c:4398 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x135f/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] =====================================================

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Meta Information

Published

2026-06-26

Last Modified

2026-07-06

Generated

2026-07-17

AI Q&A

2026-06-26

EPSS Evaluated

2026-07-15

NVD

CVE-2026-53311

EUVD

EUVD-2026-39846

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	From 6.19 (inc) to 7.0.10 (exc)
linux	linux_kernel	From 6.16 (inc) to 6.18.34 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-908	The product uses or accesses a resource that has not been initialized.

Attack-Flow Graph

Executive Summary

This vulnerability exists in the Linux kernel's FUSE (Filesystem in Userspace) component, specifically in the function fuse_dentry_revalidate(). The issue arises because fuse_dentry_revalidate() may be called with a dentry (directory entry) structure that has an uninitialized d_time field. This uninitialized value was detected by KMSAN (Kernel Memory Sanitizer) during certain file lookup operations, which can lead to undefined behavior.

Detection Guidance

This vulnerability involves an uninitialized value in the Linux kernel function fuse_dentry_revalidate(). Detection would typically require monitoring for kernel warnings or bugs related to uninitialized values in fuse_dentry_revalidate.

Since the issue was found using KMSAN (Kernel Memory Sanitizer), enabling KMSAN on your kernel and monitoring its output could help detect this vulnerability.

There are no specific commands provided to detect this vulnerability directly.

Impact Analysis

The vulnerability involves the use of uninitialized memory within the kernel's FUSE filesystem code. While the exact impact is not detailed, uninitialized memory usage can potentially lead to unpredictable behavior, including system instability or crashes. However, no direct information about exploitation or security impact such as privilege escalation or data leakage is provided.

Mitigation Strategies

The vulnerability has been resolved by fixing the uninitialized value in fuse_dentry_revalidate().

Immediate mitigation steps would include updating your Linux kernel to a version that contains this fix.

No other specific mitigation steps or workarounds are provided.

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