Linux Kernel up to 6.12.96/6.18.39/7.1.4/7.2-rc1 fhandle capable_wrt_mount null pointer dereference

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5.3	$0-$5k	0.47

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.12.96/6.18.39/7.1.4/7.2-rc1. Affected is the function capable_wrt_mount of the component fhandle. The manipulation results in null pointer dereference. This vulnerability is cataloged as CVE-2026-72034. The attack must be initiated from a local position. There is no exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.96/6.18.39/7.1.4/7.2-rc1. It has been classified as critical. Affected is the function capable_wrt_mount of the component fhandle. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-72034 since 08/09/2026. The exploitability is told to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available.

Upgrading to version 6.12.97, 6.18.40, 7.1.5 or 7.2-rc2 eliminates this vulnerability. Applying the patch 15104234c267ebe04b9f9a73e5c2179cc265ff60/6c52226072a3c61337b1eec1799bb987748884fa/6ee183d89261bf1d1cf9f06d80a40dab8f36ee55/6c732471740bc2ac9b0946134f9f551dc75f4369 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
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• 6.12.39
• 6.12.40
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• 6.12.88
• 6.12.89
• 6.12.90
• 6.12.91
• 6.12.92
• 6.12.93
• 6.12.94
• 6.12.95
• 6.12.96
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
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• 6.18.13
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• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.2-rc1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.97/6.18.40/7.1.5/7.2-rc2
Patch: 15104234c267ebe04b9f9a73e5c2179cc265ff60/6c52226072a3c61337b1eec1799bb987748884fa/6ee183d89261bf1d1cf9f06d80a40dab8f36ee55/6c732471740bc2ac9b0946134f9f551dc75f4369

Timelineinfo

08/09/2026 CVE reserved
08/15/2026 +6 days Advisory disclosed
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-72034 (🔒)
GCVE (CVE): GCVE-0-2026-72034
GCVE (VulDB): GCVE-100-390444

Entryinfo

Created: 08/15/2026 11:25
Changes: 08/15/2026 11:25 (59)
Complete: 🔍
Cache ID: 216::103

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