CVE-2026-68148 Affecting linux-6.12 package, versions <6.12.101-1~deb12u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.09% (1st percentile)

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  • Snyk IDSNYK-ECHOLATEST-LINUX612-18912474
  • published18 Aug 2026
  • disclosed10 Aug 2026

Introduced: 10 Aug 2026

CVE-2026-68148  (opens in a new tab)

How to fix?

Upgrade Echo:latest linux-6.12 to version 6.12.101-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1