Linux Kernel up to 7.2-rc2 mm file_owner_or_capable/owner_or_capable permission

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k3.11-

Summaryinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 6.6.144/6.12.95/6.18.38/7.1.3/7.2-rc2. The affected element is the function file_owner_or_capable/owner_or_capable of the component mm. The manipulation leads to permission. This vulnerability is documented as CVE-2026-64294. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.144/6.12.95/6.18.38/7.1.3/7.2-rc2 and classified as very critical. This issue affects the function file_owner_or_capable/owner_or_capable of the component mm. The manipulation with an unknown input leads to a permission vulnerability. Using CWE to declare the problem leads to CWE-275. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: mm: do file ownership checks with the proper mount idmap Ever since idmapped mounts were introduced, inode ownership checks (for side-channel protection) in mincore() and madvise(MADV_PAGEOUT) were done against the nop_mnt_idmap, which completely ignores the file's mount's idmap. This results in odd edgecases like: 1) mount/bind-mount with an idmap userA:userB:1 2) userB runs an owner_or_capable() check on file that is owned by userA on-disk/in-memory, but owned by userB after idmap translation 3) owner_or_capable() mysteriously fails as the correct idmap wasn't supplied In the case of mincore/madvise MADV_PAGEOUT, this is usually benign, because file_permission(file, MAY_WRITE) will probably succeed, as it uses the proper idmap internally, but it does not need to be the case on e.g a 0444 file where even the owner itself doesn't have permissions to write to it. Since this is clearly not trivial to get right, introduce a file_owner_or_capable() that can carry the correct semantics, and switch the various users in mm to it. The issue was found by manual code inspection & an off-list discussion with Jan Kara.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-64294 since 07/19/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/25/2026). MITRE ATT&CK project uses the attack technique T1222 for this issue.

Upgrading to version 6.6.145, 6.12.96, 6.18.39, 7.1.4 or 7.2-rc3 eliminates this vulnerability. Applying the patch 744b23aa430d52f5c8e4dbff7d71496d6643bed2/8344bdf0629457e532797b42d9d2bbf2a2900bbf/5c942ad7df75925ee166e7f0fb36892d8dde376b/04ba248d02d9eaa3d9077b00a6134caa75fa3e90/e187bc02f8fa4226d62814592cf064ee4557c470 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
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: Permission
CWE: CWE-275 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

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 6.6.145/6.12.96/6.18.39/7.1.4/7.2-rc3
Patch: 744b23aa430d52f5c8e4dbff7d71496d6643bed2/8344bdf0629457e532797b42d9d2bbf2a2900bbf/5c942ad7df75925ee166e7f0fb36892d8dde376b/04ba248d02d9eaa3d9077b00a6134caa75fa3e90/e187bc02f8fa4226d62814592cf064ee4557c470

Timelineinfo

07/19/2026 CVE reserved
07/25/2026 +6 days Advisory disclosed
07/25/2026 +0 days VulDB entry created
07/25/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64294 (🔒)
GCVE (CVE): GCVE-0-2026-64294
GCVE (VulDB): GCVE-100-383081

Entryinfo

Created: 07/25/2026 13:39
Changes: 07/25/2026 13:39 (59)
Complete: 🔍
Cache ID: 216::103

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