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7.8
HIGH CVSS 3.1
CVE-2026-53341
fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh()
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh() may_decode_fh() accesses mount::mnt_ns without holding any locks; that means the mount can concurrently be unmounted, and the mnt_namespace can concurrently be freed after an RCU grace period. This race can happens as follows, assuming that the mount point was created by open_tree(..., OPEN_TREE_CLONE): thread 1 thread 2 RCU __do_sys_open_by_handle_at do_handle_open handle_to_path may_decode_fh is_mounted [mount::mnt_ns access] [mount::mnt_ns access] __do_sys_close fput_close_sync __fput dissolve_on_fput umount_tree class_namespace_excl_destructor namespace_unlock free_mnt_ns mnt_ns_tree_remove call_rcu(mnt_ns_release_rcu) mnt_ns_release_rcu mnt_ns_release kfree [mnt_namespace::user_ns access] **UAF** Fix it by taking rcu_read_lock() around the mount::mnt_ns access, like in __prepend_path(). Additionally, document the semantics of mount::mnt_ns, and use WRITE_ONCE() for writers that can race with lockless readers. This bug is unreachable unless one of the following is set: - CONFIG_PREEMPTION - CONFIG_RCU_STRICT_GRACE_PERIOD because it requires an RCU grace period to happen during a syscall without an explicit preemption. This doesn't seem to have interesting security impact; worst-case, it could leak the result of an integer comparison to userspace (from the level check in cap_capable()), cause an endless loop, or crash the kernel by dereferencing an invalid address.

Details
INFO

Published Date :

July 1, 2026, 2:16 p.m.

Last Modified :

July 23, 2026, 9:32 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-53341 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Address a use-after-free flaw by locking mount namespace access during concurrent operations.
  • Lock mount namespace access with rcu_read_lock() before reading mnt_ns.
  • Document mount::mnt_ns semantics for readers and writers.
  • Use WRITE_ONCE() for writers that race with lockless readers.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-53341.

URL Resource
https://git.kernel.org/stable/c/15ea8dc42a02259d49dee38a658d40f60fcd75ed Patch
https://git.kernel.org/stable/c/32138633e51e6db59e474765cf93268c92b42888 Patch
https://git.kernel.org/stable/c/40ab6644b99685755f740b872c00ef40d9aa870e Patch
https://git.kernel.org/stable/c/a8ed2c29fcfdac78db96c9da4e659c8a513f2a94 Patch
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-53341 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-53341 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-53341 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-53341 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Jul. 23, 2026

    Action Type Old Value New Value
    Added CWE CWE-416
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.36 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.13 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.11 up to (excluding) 6.12.95
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/15ea8dc42a02259d49dee38a658d40f60fcd75ed Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/32138633e51e6db59e474765cf93268c92b42888 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/40ab6644b99685755f740b872c00ef40d9aa870e Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/a8ed2c29fcfdac78db96c9da4e659c8a513f2a94 Types: Patch
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 18, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 04, 2026

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/15ea8dc42a02259d49dee38a658d40f60fcd75ed
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '32138633e51e6db59e474765cf93268c92b42888', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': 'a8ed2c29fcfdac78db96c9da4e659c8a513f2a94', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '40ab6644b99685755f740b872c00ef40d9aa870e', 'versionType': 'git'}], 'programFiles': ['fs/fhandle.c', 'fs/mount.h', 'fs/namespace.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.11'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.11', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fhandle.c', 'fs/mount.h', 'fs/namespace.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '15ea8dc42a02259d49dee38a658d40f60fcd75ed', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '32138633e51e6db59e474765cf93268c92b42888', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': 'a8ed2c29fcfdac78db96c9da4e659c8a513f2a94', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '40ab6644b99685755f740b872c00ef40d9aa870e', 'versionType': 'git'}], 'programFiles': ['fs/fhandle.c', 'fs/mount.h', 'fs/namespace.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.11'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.11', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.95', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fhandle.c', 'fs/mount.h', 'fs/namespace.c'], 'defaultStatus': 'affected'}]
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 01, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '32138633e51e6db59e474765cf93268c92b42888', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': 'a8ed2c29fcfdac78db96c9da4e659c8a513f2a94', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '40ab6644b99685755f740b872c00ef40d9aa870e', 'versionType': 'git'}], 'programFiles': ['fs/fhandle.c', 'fs/mount.h', 'fs/namespace.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.11'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.11', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fhandle.c', 'fs/mount.h', 'fs/namespace.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh() may_decode_fh() accesses mount::mnt_ns without holding any locks; that means the mount can concurrently be unmounted, and the mnt_namespace can concurrently be freed after an RCU grace period. This race can happens as follows, assuming that the mount point was created by open_tree(..., OPEN_TREE_CLONE): thread 1 thread 2 RCU __do_sys_open_by_handle_at do_handle_open handle_to_path may_decode_fh is_mounted [mount::mnt_ns access] [mount::mnt_ns access] __do_sys_close fput_close_sync __fput dissolve_on_fput umount_tree class_namespace_excl_destructor namespace_unlock free_mnt_ns mnt_ns_tree_remove call_rcu(mnt_ns_release_rcu) mnt_ns_release_rcu mnt_ns_release kfree [mnt_namespace::user_ns access] **UAF** Fix it by taking rcu_read_lock() around the mount::mnt_ns access, like in __prepend_path(). Additionally, document the semantics of mount::mnt_ns, and use WRITE_ONCE() for writers that can race with lockless readers. This bug is unreachable unless one of the following is set: - CONFIG_PREEMPTION - CONFIG_RCU_STRICT_GRACE_PERIOD because it requires an RCU grace period to happen during a syscall without an explicit preemption. This doesn't seem to have interesting security impact; worst-case, it could leak the result of an integer comparison to userspace (from the level check in cap_capable()), cause an endless loop, or crash the kernel by dereferencing an invalid address.
    Added Reference https://git.kernel.org/stable/c/32138633e51e6db59e474765cf93268c92b42888
    Added Reference https://git.kernel.org/stable/c/40ab6644b99685755f740b872c00ef40d9aa870e
    Added Reference https://git.kernel.org/stable/c/a8ed2c29fcfdac78db96c9da4e659c8a513f2a94
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 7.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact