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7.8
HIGH CVSS 3.1
CVE-2026-72034
fhandle: reject detached mounts in capable_wrt_mount()
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: fhandle: reject detached mounts in capable_wrt_mount() The recent fhandle RCU fix moved the mount namespace capability check into capable_wrt_mount(), so a non-NULL mnt_namespace survives the ns_capable() dereference. The helper still assumes the later READ_ONCE(mount->mnt_ns) must be non-NULL because may_decode_fh() checked is_mounted() first. That assumption is not stable. A detached mount from open_tree(..., OPEN_TREE_CLONE) can be dissolved on fput while open_by_handle_at() is between those checks, and umount_tree() can clear mount->mnt_ns. If the helper observes NULL, it dereferences mnt_ns->user_ns and panics. Return false when the RCU read observes a detached mount. This keeps the relaxed permission path conservative: a mount no longer attached to a namespace cannot authorize open_by_handle_at() access.

Details
INFO

Published Date :

Aug. 15, 2026, 6:21 a.m.

Last Modified :

Aug. 17, 2026, 6:18 a.m.

Remotely Exploit :

No

Source :

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

The following products are affected by CVE-2026-72034 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
Apply kernel updates to fix the detached mount issue in capable_wrt_mount.
  • Update the Linux kernel.
  • Apply the provided patch for fhandle.
  • Reboot the system after updates.
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-2026-72034.

URL Resource
https://git.kernel.org/stable/c/15104234c267ebe04b9f9a73e5c2179cc265ff60
https://git.kernel.org/stable/c/6c52226072a3c61337b1eec1799bb987748884fa
https://git.kernel.org/stable/c/6c732471740bc2ac9b0946134f9f551dc75f4369
https://git.kernel.org/stable/c/6ee183d89261bf1d1cf9f06d80a40dab8f36ee55
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-72034 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-2026-72034 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-2026-72034 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-2026-72034 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.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 17, 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
    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': '15104234c267ebe04b9f9a73e5c2179cc265ff60', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6c52226072a3c61337b1eec1799bb987748884fa', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6ee183d89261bf1d1cf9f06d80a40dab8f36ee55', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6c732471740bc2ac9b0946134f9f551dc75f4369', 'versionType': 'git'}], 'programFiles': ['fs/fhandle.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': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fhandle.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': '15104234c267ebe04b9f9a73e5c2179cc265ff60', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6c52226072a3c61337b1eec1799bb987748884fa', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6ee183d89261bf1d1cf9f06d80a40dab8f36ee55', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6c732471740bc2ac9b0946134f9f551dc75f4369', 'versionType': 'git'}], 'programFiles': ['fs/fhandle.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': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fhandle.c'], 'defaultStatus': 'affected'}]
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 15, 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': '15104234c267ebe04b9f9a73e5c2179cc265ff60', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6c52226072a3c61337b1eec1799bb987748884fa', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6ee183d89261bf1d1cf9f06d80a40dab8f36ee55', 'versionType': 'git'}, {'status': 'affected', 'version': '620c266f394932e5decc4b34683a75dfc59dc2f4', 'lessThan': '6c732471740bc2ac9b0946134f9f551dc75f4369', 'versionType': 'git'}], 'programFiles': ['fs/fhandle.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': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fhandle.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: fhandle: reject detached mounts in capable_wrt_mount() The recent fhandle RCU fix moved the mount namespace capability check into capable_wrt_mount(), so a non-NULL mnt_namespace survives the ns_capable() dereference. The helper still assumes the later READ_ONCE(mount->mnt_ns) must be non-NULL because may_decode_fh() checked is_mounted() first. That assumption is not stable. A detached mount from open_tree(..., OPEN_TREE_CLONE) can be dissolved on fput while open_by_handle_at() is between those checks, and umount_tree() can clear mount->mnt_ns. If the helper observes NULL, it dereferences mnt_ns->user_ns and panics. Return false when the RCU read observes a detached mount. This keeps the relaxed permission path conservative: a mount no longer attached to a namespace cannot authorize open_by_handle_at() access.
    Added Reference https://git.kernel.org/stable/c/15104234c267ebe04b9f9a73e5c2179cc265ff60
    Added Reference https://git.kernel.org/stable/c/6c52226072a3c61337b1eec1799bb987748884fa
    Added Reference https://git.kernel.org/stable/c/6c732471740bc2ac9b0946134f9f551dc75f4369
    Added Reference https://git.kernel.org/stable/c/6ee183d89261bf1d1cf9f06d80a40dab8f36ee55
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
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