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fscrypt: Add missing superblock check in find_or_insert_direct_key()

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-68148

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-68148

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "22e9947a4b2ba255888541bd0111cf00b9b16586",
        "lessThan": "965b5bc8cf5031225e057979ce660fec2bd5fbfc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "22e9947a4b2ba255888541bd0111cf00b9b16586",
        "lessThan": "330249609b70778094a7a36f5b6bcfa6362121d4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "22e9947a4b2ba255888541bd0111cf00b9b16586",
        "lessThan": "deff41898a5ae3a47db5fa1896a494aa95efda5d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "22e9947a4b2ba255888541bd0111cf00b9b16586",
        "lessThan": "95376fe9c145be35566991df99c53134943d992f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "22e9947a4b2ba255888541bd0111cf00b9b16586",
        "lessThan": "466f187b501a5ac8e1ea2ccf3ccd5c46108d8830",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "22e9947a4b2ba255888541bd0111cf00b9b16586",
        "lessThan": "b5fa40226e71c17847b9ff2816c6ca4133d0d994",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/crypto/keysetup_v1.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.1"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.1",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.148",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.101",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.42",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/crypto/keysetup_v1.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-68148

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#41137 · Revision 1
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Publisher date
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