{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47412", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-21T14:58:30.817Z", "datePublished": "2024-05-21T15:04:03.309Z", "dateUpdated": "2026-08-05T08:47:43.235Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:47:43.235Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: don't call rq_qos_ops->done_bio if the bio isn't tracked\n\nrq_qos framework is only applied on request based driver, so:\n\n1) rq_qos_done_bio() needn't to be called for bio based driver\n\n2) rq_qos_done_bio() needn't to be called for bio which isn't tracked,\nsuch as bios ended from error handling code.\n\nEspecially in bio_endio():\n\n1) request queue is referred via bio->bi_bdev->bd_disk->queue, which\nmay be gone since request queue refcount may not be held in above two\ncases\n\n2) q->rq_qos may be freed in blk_cleanup_queue() when calling into\n__rq_qos_done_bio()\n\nFix the potential kernel panic by not calling rq_qos_ops->done_bio if\nthe bio isn't tracked. This way is safe because both ioc_rqos_done_bio()\nand blkcg_iolatency_done_bio() are nop if the bio isn't tracked." } ], "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 bug is in block-layer bio_endio()/rq_qos_done_bio(), reached by local I/O submission (syscalls to a block device or filesystem on it) racing device/queue teardown, not by parsing remote protocol packets.\nAC:L - An attacker who can issue concurrent I/O and induce queue teardown (e.g. write to removable/loop/NBD media then eject/disconnect) controls both sides of the race; rq_qos_done_bio() has no lock versus rq_qos_exit(), so the UAF is reliably triggerable.\nPR:L - Unprivileged local users can write to user-accessible block devices (removable media, permitted loop/NBD nodes) and trigger teardown via eject/unmount paths available to the mounting user; root in the init namespace is not required.\nUI:N - The attacker performs the I/O and device teardown/eject themselves; no separate victim action is required.\nS:U - Impact is confined to the host kernel (UAF/panic or local privilege escalation) and does not cross a VM, IOMMU, or other security authority boundary.\nC:H - rq_qos_exit() frees rq_qos objects while bio_endio() may still load q->rq_qos and walk rqos->ops/next on reallocated slab memory, giving an attacker-controlled UAF read primitive.\nI:H - __rq_qos_done_bio() invokes rqos->ops->done_bio on the freed object, so heap reuse can hijack the function pointer for arbitrary write / control-flow hijacking, not merely a crash.\nA:H - The same UAF produces kernel oops/panic when done_bio runs against freed rq_qos or a freed request_queue, fully impacting availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/bio.c" ], "versions": [ { "version": "67b42d0bf7a8fd1ec0cf1acdc9550e688d7c8578", "lessThan": "db60edbfff332a6a5477c367af8125f034570989", "status": "affected", "versionType": "git" }, { "version": "67b42d0bf7a8fd1ec0cf1acdc9550e688d7c8578", "lessThan": "004b8f8a691205a93d9e80d98b786b2b97424d6e", "status": "affected", "versionType": "git" }, { "version": "67b42d0bf7a8fd1ec0cf1acdc9550e688d7c8578", "lessThan": "a647a524a46736786c95cdb553a070322ca096e3", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/bio.c" ], "versions": [ { "version": "4.19", "status": "affected" }, { "version": "0", "lessThan": "4.19", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.241", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.14.11", "lessThanOrEqual": "5.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15", "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": "4.19", "versionEndExcluding": "5.10.241" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "5.14.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "5.15" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/db60edbfff332a6a5477c367af8125f034570989" }, { "url": "https://git.kernel.org/stable/c/004b8f8a691205a93d9e80d98b786b2b97424d6e" }, { "url": "https://git.kernel.org/stable/c/a647a524a46736786c95cdb553a070322ca096e3" } ], "title": "block: don't call rq_qos_ops->done_bio if the bio isn't tracked", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-06-11T17:28:47.066559Z", "id": "CVE-2021-47412", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-11T17:29:00.823Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/004b8f8a691205a93d9e80d98b786b2b97424d6e", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/a647a524a46736786c95cdb553a070322ca096e3", "tags": [ "x_transferred" ] }, { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:30:56.004Z" } } ] } }