Linux Kernel up to 7.2-rc4 fscrypt find_or_insert_direct_key use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k1.79-

Summaryinfo

A vulnerability marked as very critical has been reported in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4. The affected element is the function find_or_insert_direct_key of the component fscrypt. The manipulation leads to use after free. This vulnerability is listed as CVE-2026-68148. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4. It has been rated as very critical. This issue affects the function find_or_insert_direct_key of the component fscrypt. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: fscrypt: Add missing superblock check in find_or_insert_direct_key() The legacy 'fscrypt_direct_keys' table caches master keys that are used by v1 encryption policies that have FSCRYPT_POLICY_FLAG_DIRECT_KEY. It's just a global table for all filesystems (since the keys can be provided by the legacy process-subscribed keyrings mechanism, which makes it difficult to reuse super_block::s_master_keys). The entries in it ('struct fscrypt_direct_key') do contain a super_block pointer, though, for passing to fscrypt_destroy_inline_crypt_key() when the last inode that references the key is evicted. However, when finding the fscrypt_direct_key for an inode, we weren't actually comparing the super_block pointer. As a result, inodes with different super_blocks could point to the same fscrypt_direct_key. That could extend the lifetime of a fscrypt_direct_key beyond the super_block it points to, causing a use-after-free later. Fix this by creating distinct fscrypt_direct_key structs for distinct super_block structs. Note that this problem doesn't exist in the v2 policy equivalent ("per-mode keys"), since the data structures there are per super_block.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-68148 since 07/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/10/2026).

Upgrading to version 6.6.148, 6.12.101, 6.18.42, 7.1.6 or 7.2-rc5 eliminates this vulnerability. Applying the patch 330249609b70778094a7a36f5b6bcfa6362121d4/deff41898a5ae3a47db5fa1896a494aa95efda5d/95376fe9c145be35566991df99c53134943d992f/466f187b501a5ac8e1ea2ccf3ccd5c46108d8830/b5fa40226e71c17847b9ff2816c6ca4133d0d994 is able to eliminate this problem.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

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: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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 6.6.148/6.12.101/6.18.42/7.1.6/7.2-rc5
Patch: 330249609b70778094a7a36f5b6bcfa6362121d4/deff41898a5ae3a47db5fa1896a494aa95efda5d/95376fe9c145be35566991df99c53134943d992f/466f187b501a5ac8e1ea2ccf3ccd5c46108d8830/b5fa40226e71c17847b9ff2816c6ca4133d0d994

Timelineinfo

07/30/2026 CVE reserved
08/10/2026 +11 days Advisory disclosed
08/10/2026 +0 days VulDB entry created
08/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-68148 (🔒)
GCVE (CVE): GCVE-0-2026-68148
GCVE (VulDB): GCVE-100-387503

Entryinfo

Created: 08/10/2026 15:27
Changes: 08/10/2026 15:27 (59)
Complete: 🔍
Cache ID: 216::103

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