{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47600", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-24T15:11:00.736Z", "datePublished": "2024-06-19T14:54:00.981Z", "dateUpdated": "2026-08-05T08:48:32.894Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:48:32.894Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm btree remove: fix use after free in rebalance_children()\n\nMove dm_tm_unlock() after dm_tm_dec()." } ], "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 UAF is in dm-btree rebalance_children(), reached via local dm-thin metadata updates (discard → dm_thin_remove_range → dm_btree_remove/remove_leaves) or CAP_SYS_ADMIN dm-ioctl pool messages, not via network or adjacent protocols.\nAC:L - An attacker who can discard/unmap on a thin volume fully drives btree shrinkage into the single-child collapse path where unlock precedes dm_block_location(); no conditions outside attacker control are required, and UAFs are AC:L per guidance.\nPR:L - On hosts already using dm-thin/LVM thin pools, an unprivileged user with access to a thin-backed filesystem or device can issue discards (e.g. deletes under discard mounts or BLKDISCARD) that hit this path; creating the pool needs CAP_SYS_ADMIN but is a deployment precondition.\nUI:N - The attacker triggers the vulnerable remove/rebalance path themselves through their own I/O or ioctls; no separate victim action is required.\nS:U - This is a host-kernel heap use-after-free within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Unlocking the child block then reading dm_block_location(child) is a use-after-free on the bufio buffer; reclaim/spray of that object enables arbitrary kernel memory disclosure.\nI:H - The UAF can feed an attacker-controlled block number into dm_tm_dec(), corrupting the space map and yielding heap/metadata corruption primitives exploitable for arbitrary write and control-flow hijack.\nA:H - Any use-after-free can oops/panic the kernel (KASAN UAF or invalid access after reclaim), fully impacting availability even without successful code execution." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/md/persistent-data/dm-btree-remove.c" ], "versions": [ { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "a48f6a2bf33734ec5669ee03067dfb6c5b4818d6", "status": "affected", "versionType": "git" }, { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "66ea642af6fd4eacb5d0271a922130fcf8700424", "status": "affected", "versionType": "git" }, { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "b03abd0aa09c05099f537cb05b8460c4298f0861", "status": "affected", "versionType": "git" }, { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "293f957be5e39720778fb1851ced7f5fba6d51c3", "status": "affected", "versionType": "git" }, { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "501ecd90efdc9b2edc6c28852ecd098a4adf8f00", "status": "affected", "versionType": "git" }, { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "0e21e6cd5eebfc929ac5fa3b97ca2d4ace3cb6a3", "status": "affected", "versionType": "git" }, { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "607beb420b3fe23b948a9bf447d993521a02fbbb", "status": "affected", "versionType": "git" }, { "version": "3241b1d3e0aaafbfcd320f4d71ade629728cc4f4", "lessThan": "1b8d2789dad0005fd5e7d35dab26a8e1203fb6da", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/md/persistent-data/dm-btree-remove.c" ], "versions": [ { "version": "3.2", "status": "affected" }, { "version": "0", "lessThan": "3.2", "status": "unaffected", "versionType": "semver" }, { "version": "4.4.296", "lessThanOrEqual": "4.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.294", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.259", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.222", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.168", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.88", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.11", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.16", "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": "3.2", "versionEndExcluding": "4.4.296" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "4.9.294" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "4.14.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "4.19.222" 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