Linux Kernel up to 7.2-rc1 vfs_tmpfile access control

CVSS Meta Temp Score
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CTI Interest Score
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4.2$0-$5k0.47+

Summaryinfo

A vulnerability classified as problematic has been found in Linux Kernel up to 6.6.144/6.12.96/6.18.39/7.1.4/7.2-rc1. This issue affects the function vfs_tmpfile. The manipulation leads to access control. This vulnerability is uniquely identified as CVE-2026-72379. Local access is required to approach this attack. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.144/6.12.96/6.18.39/7.1.4/7.2-rc1. It has been rated as problematic. This issue affects the function vfs_tmpfile. The manipulation with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: fs: refuse O_TMPFILE creation with an unmapped fsuid or fsgid vfs_tmpfile() never checked that the caller's fsuid and fsgid map into the filesystem. On an idmapped mount whose idmapping does not cover the caller's fs{u,g}id, the ->tmpfile() instance initializes the new inode through inode_init_owner(), where mapped_fsuid()/mapped_fsgid() return INVALID_UID/INVALID_GID, and the tmpfile ends up owned by (uid_t)-1. Every other creation path already refuses this: may_o_create() (O_CREAT) and may_create_dentry() (mkdir, mknod, symlink, link) bail out with -EOVERFLOW via fsuidgid_has_mapping() precisely so that an object cannot be created with an owner the filesystem cannot represent. An O_TMPFILE is no exception: it is created I_LINKABLE and linkat(2) can splice it into the namespace afterwards, so the same guarantee must hold. Add the missing fsuidgid_has_mapping() check to vfs_tmpfile(). On a non-idmapped mount the caller's fs{u,g}id always map in the superblock's user namespace, so this is a no-op there and only takes effect on an idmapped mount that does not map the caller. It applies to every filesystem that sets FS_ALLOW_IDMAP and implements ->tmpfile() (tmpfs, ext4, btrfs, xfs, f2fs, ...), and to overlayfs, whose upper-layer tmpfile creation funnels through vfs_tmpfile() via backing_tmpfile_open().

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-72379 since 08/09/2026. The exploitation is known to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026). MITRE ATT&CK project uses the attack technique T1068 for this issue.

Upgrading to version 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc2 eliminates this vulnerability. Applying the patch bac8fb0d60254846f3b56957435dcd870ae12948/503d0568a525b168d9aa5ca046ec72fc5477df84/a2038514e69371eb493083a6a897ed20fcbb8acb/47e434da476b5a8bcd1e6e52ab03c5ee7764ee78/539dce1144651f7976fa418e618b0b574bf15eeb is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.4
VulDB Temp Score: 4.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

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

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc2
Patch: bac8fb0d60254846f3b56957435dcd870ae12948/503d0568a525b168d9aa5ca046ec72fc5477df84/a2038514e69371eb493083a6a897ed20fcbb8acb/47e434da476b5a8bcd1e6e52ab03c5ee7764ee78/539dce1144651f7976fa418e618b0b574bf15eeb

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-2026-72379 (🔒)
GCVE (CVE): GCVE-0-2026-72379
GCVE (VulDB): GCVE-100-390977

Entryinfo

Created: 08/15/2026 16:45
Changes: 08/15/2026 16:45 (58)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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