{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68148", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.371Z", "datePublished": "2026-08-10T11:59:13.413Z", "dateUpdated": "2026-08-19T16:30:13.417Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:30:13.417Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfscrypt: Add missing superblock check in find_or_insert_direct_key()\n\nThe legacy 'fscrypt_direct_keys' table caches master keys that are used\nby v1 encryption policies that have FSCRYPT_POLICY_FLAG_DIRECT_KEY.\nIt's just a global table for all filesystems (since the keys can be\nprovided by the legacy process-subscribed keyrings mechanism, which\nmakes it difficult to reuse super_block::s_master_keys).\n\nThe entries in it ('struct fscrypt_direct_key') do contain a super_block\npointer, though, for passing to fscrypt_destroy_inline_crypt_key() when\nthe last inode that references the key is evicted.\n\nHowever, when finding the fscrypt_direct_key for an inode, we weren't\nactually comparing the super_block pointer. As a result, inodes with\ndifferent super_blocks could point to the same fscrypt_direct_key. That\ncould extend the lifetime of a fscrypt_direct_key beyond the\nsuper_block it points to, causing a use-after-free later.\n\nFix this by creating distinct fscrypt_direct_key structs for distinct\nsuper_block structs.\n\nNote that this problem doesn't exist in the v2 policy equivalent\n(\"per-mode keys\"), since the data structures there are per super_block." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The flaw is reached only through local syscalls (mount/umount, FS_IOC_SET_ENCRYPTION_POLICY, and file I/O that calls fscrypt_get_encryption_info -> find_or_insert_direct_key); fscrypt is not invoked from network-facing kernel services.\nAC:L - An attacker who can mount two encrypted filesystems with the same v1 DIRECT_KEY master key, share the global cache entry, then unmount the first superblock can deterministically trigger eviction-time cleanup on a freed super_block without races or victim-dependent timing.\nPR:L - Exploitation requires mounting/unmounting filesystems and setting v1 DIRECT_KEY policies (CAP_SYS_ADMIN in a user/mount namespace) or supplying keys via process keyrings; per kernel guidance, CAP_SYS_ADMIN obtainable in user namespaces maps to PR:L.\nUI:N - No separate victim action is required; the attacker sets v1 DIRECT_KEY policies, accesses encrypted inodes on two mounts, and controls unmount/eviction to hit the vulnerable refcount and cleanup path.\nS:U - The use-after-free corrupts kernel heap memory and enables local privilege escalation within the same kernel; it does not cross VM, hypervisor, or IOMMU security boundaries.\nC:H - Extending a fscrypt_direct_key past its super_block lifetime causes cleanup to dereference a freed super_block in fscrypt_destroy_inline_crypt_key(), a use-after-free that can leak kernel memory and support arbitrary-read exploitation primitives.\nI:H - Use-after-free during inline-crypto key destruction on a dangling super_block pointer can be leveraged for heap corruption and arbitrary kernel writes, enabling local privilege escalation rather than only a controlled crash.\nA:H - Evicting the last inode holding the mismatched fscrypt_direct_key dereferences a freed super_block during key teardown, which can cause kernel oops/panic and complete local denial of service on encrypted mobile/embedded and server systems using inline encryption." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/crypto/keysetup_v1.c" ], "versions": [ { "version": "22e9947a4b2ba255888541bd0111cf00b9b16586", "lessThan": "965b5bc8cf5031225e057979ce660fec2bd5fbfc", "status": "affected", "versionType": "git" }, { "version": "22e9947a4b2ba255888541bd0111cf00b9b16586", "lessThan": "330249609b70778094a7a36f5b6bcfa6362121d4", "status": "affected", "versionType": "git" }, { "version": "22e9947a4b2ba255888541bd0111cf00b9b16586", "lessThan": "deff41898a5ae3a47db5fa1896a494aa95efda5d", "status": "affected", "versionType": "git" }, { "version": "22e9947a4b2ba255888541bd0111cf00b9b16586", "lessThan": "95376fe9c145be35566991df99c53134943d992f", "status": "affected", "versionType": "git" }, { "version": "22e9947a4b2ba255888541bd0111cf00b9b16586", "lessThan": "466f187b501a5ac8e1ea2ccf3ccd5c46108d8830", "status": "affected", "versionType": "git" }, { "version": "22e9947a4b2ba255888541bd0111cf00b9b16586", "lessThan": "b5fa40226e71c17847b9ff2816c6ca4133d0d994", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/crypto/keysetup_v1.c" ], "versions": [ { "version": "6.1", "status": "affected" }, { "version": "0", "lessThan": "6.1", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/965b5bc8cf5031225e057979ce660fec2bd5fbfc" }, { "url": "https://git.kernel.org/stable/c/330249609b70778094a7a36f5b6bcfa6362121d4" }, { "url": "https://git.kernel.org/stable/c/deff41898a5ae3a47db5fa1896a494aa95efda5d" }, { "url": "https://git.kernel.org/stable/c/95376fe9c145be35566991df99c53134943d992f" }, { "url": "https://git.kernel.org/stable/c/466f187b501a5ac8e1ea2ccf3ccd5c46108d8830" }, { "url": "https://git.kernel.org/stable/c/b5fa40226e71c17847b9ff2816c6ca4133d0d994" } ], "title": "fscrypt: Add missing superblock check in find_or_insert_direct_key()", "x_generator": { "engine": "bippy-1.2.0" } } } }