{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-47706", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-09-30T16:00:12.946Z", "datePublished": "2024-10-21T11:53:40.759Z", "dateUpdated": "2026-08-05T11:39:37.119Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:39:37.119Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix possible UAF for bfqq->bic with merge chain\n\n1) initial state, three tasks:\n\n\t\tProcess 1 Process 2\tProcess 3\n\t\t (BIC1) (BIC2)\t\t (BIC3)\n\t\t | Λ | Λ\t\t | Λ\n\t\t | | | |\t\t | |\n\t\t V | V |\t\t V |\n\t\t bfqq1 bfqq2\t\t bfqq3\nprocess ref:\t 1\t\t 1\t\t 1\n\n2) bfqq1 merged to bfqq2:\n\n\t\tProcess 1 Process 2\tProcess 3\n\t\t (BIC1) (BIC2)\t\t (BIC3)\n\t\t | |\t\t | Λ\n\t\t \\--------------\\|\t\t | |\n\t\t V\t\t V |\n\t\t bfqq1--------->bfqq2\t\t bfqq3\nprocess ref:\t 0\t\t 2\t\t 1\n\n3) bfqq2 merged to bfqq3:\n\n\t\tProcess 1 Process 2\tProcess 3\n\t\t (BIC1) (BIC2)\t\t (BIC3)\n\t here -> Λ |\t\t |\n\t\t \\--------------\\ \\-------------\\|\n\t\t V\t\t V\n\t\t bfqq1--------->bfqq2---------->bfqq3\nprocess ref:\t 0\t\t 1\t\t 3\n\nIn this case, IO from Process 1 will get bfqq2 from BIC1 first, and then\nget bfqq3 through merge chain, and finially handle IO by bfqq3.\nHowerver, current code will think bfqq2 is owned by BIC1, like initial\nstate, and set bfqq2->bic to BIC1.\n\nbfq_insert_request\n-> by Process 1\n bfqq = bfq_init_rq(rq)\n bfqq = bfq_get_bfqq_handle_split\n bfqq = bic_to_bfqq\n -> get bfqq2 from BIC1\n bfqq->ref++\n rq->elv.priv[0] = bic\n rq->elv.priv[1] = bfqq\n if (bfqq_process_refs(bfqq) == 1)\n bfqq->bic = bic\n -> record BIC1 to bfqq2\n\n __bfq_insert_request\n new_bfqq = bfq_setup_cooperator\n -> get bfqq3 from bfqq2->new_bfqq\n bfqq_request_freed(bfqq)\n new_bfqq->ref++\n rq->elv.priv[1] = new_bfqq\n -> handle IO by bfqq3\n\nFix the problem by checking bfqq is from merge chain fist. And this\nmight fix a following problem reported by our syzkaller(unreproducible):\n\n==================================================================\nBUG: KASAN: slab-use-after-free in bfq_do_early_stable_merge block/bfq-iosched.c:5692 [inline]\nBUG: KASAN: slab-use-after-free in bfq_do_or_sched_stable_merge block/bfq-iosched.c:5805 [inline]\nBUG: KASAN: slab-use-after-free in bfq_get_queue+0x25b0/0x2610 block/bfq-iosched.c:5889\nWrite of size 1 at addr ffff888123839eb8 by task kworker/0:1H/18595\n\nCPU: 0 PID: 18595 Comm: kworker/0:1H Tainted: G L 6.6.0-07439-gba2303cacfda #6\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014\nWorkqueue: kblockd blk_mq_requeue_work\nCall Trace:\n \n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x91/0xf0 lib/dump_stack.c:106\n print_address_description mm/kasan/report.c:364 [inline]\n print_report+0x10d/0x610 mm/kasan/report.c:475\n kasan_report+0x8e/0xc0 mm/kasan/report.c:588\n bfq_do_early_stable_merge block/bfq-iosched.c:5692 [inline]\n bfq_do_or_sched_stable_merge block/bfq-iosched.c:5805 [inline]\n bfq_get_queue+0x25b0/0x2610 block/bfq-iosched.c:5889\n bfq_get_bfqq_handle_split+0x169/0x5d0 block/bfq-iosched.c:6757\n bfq_init_rq block/bfq-iosched.c:6876 [inline]\n bfq_insert_request block/bfq-iosched.c:6254 [inline]\n bfq_insert_requests+0x1112/0x5cf0 block/bfq-iosched.c:6304\n blk_mq_insert_request+0x290/0x8d0 block/blk-mq.c:2593\n blk_mq_requeue_work+0x6bc/0xa70 block/blk-mq.c:1502\n process_one_work kernel/workqueue.c:2627 [inline]\n process_scheduled_works+0x432/0x13f0 kernel/workqueue.c:2700\n worker_thread+0x6f2/0x1160 kernel/workqueue.c:2781\n kthread+0x33c/0x440 kernel/kthread.c:388\n ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:305\n \n\nAllocated by task 20776:\n kasan_save_stack+0x20/0x40 mm/kasan/common.c:45\n kasan_set_track+0x25/0x30 mm/kasan/common.c:52\n __kasan_slab_alloc+0x87/0x90 mm/kasan/common.c:328\n kasan_slab_alloc include/linux/kasan.h:188 [inline]\n slab_post_alloc_hook mm/slab.h:763 [inline]\n slab_alloc_node mm/slub.c:3458 [inline]\n kmem_cache_alloc_node+0x1a4/0x6f0 mm/slub.c:3503\n ioc_create_icq block/blk-ioc.c:370 [inline]\n---truncated---" } ], "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 the BFQ I/O scheduler and is reached through ordinary block I/O submission (read/write/fsync on a device using the bfq elevator), which requires local access to the system. There is no network-facing path to bfq queue merging.\nAC:L - The attacker controls every precondition — it forks the cooperating processes that build the bfqq merge chain, drives the sync I/O pattern that triggers early/stable merging, and chooses when to exit a process to free its bfq_io_cq — so the dangling bfqq->bic can be created and dereferenced deterministically, and the freed slab object is refilled from the same cache by simply spawning more I/O tasks.\nPR:L - Only an unprivileged local user account is needed; no capability, namespace trick, or admin right is checked on the bfq_prepare_request/bfq_insert_request path — issuing I/O to any file on a bfq-managed device suffices.\nUI:N - The attacker's own processes generate all the I/O and the process exit that frees the bfq_io_cq; no action by any other user is required.\nS:U - The corruption is confined to kernel heap objects managed by the block layer within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - The stale bfqq->bic is read back through bfq_bfqq_resume_state()/bic_to_bfqq(), pulling bfq_queue pointers and saved state out of a freed 1360-byte object the attacker can reclaim and control, giving an information-disclosure/arbitrary-read primitive on kernel memory.\nI:H - bfq_do_early_stable_merge() and bfq_bfqq_save_state() perform writes into the freed bfq_io_cq (the KASAN slab-use-after-free write in the report), and the pointers read back out are dereferenced as live bfq_queues, which is exploitable for heap corruption and control-flow hijack.\nA:H - The use-after-free reliably corrupts kernel heap state and causes oops/panic (the reported KASAN slab-use-after-free in bfq_get_queue from a kblockd worker), crashing the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/bfq-iosched.c" ], "versions": [ { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "a9bdd5b36887d2bacb8bc777fd18317c99fc2587", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "bc2140534b2aae752e4f7cb4489642dbb5ec4777", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "e1277ae780cca4e69ef5468d4582dfd48f0b8320", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "8aa9de02a4be2e7006e636816ce19b0d667ceaa3", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "ddbdaad123254fb53e32480cb74a486a6868b1e0", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "7faed2896d78e48ec96229e73b30b0af6c00a9aa", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "880692ee233ba63808182705b3333403413b58f5", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "6d130db286ad0ea392c96ebb2551acf0d7308048", "status": "affected", "versionType": "git" }, { "version": "36eca894832351feed9072d0f97eb06fc9482ca4", "lessThan": "18ad4df091dd5d067d2faa8fce1180b79f7041a7", "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/bfq-iosched.c" ], "versions": [ { "version": "4.12", "status": "affected" }, { "version": "0", "lessThan": "4.12", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.323", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.285", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.227", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.168", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.113", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.54", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.10.13", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11.2", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12", "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": "4.12", "versionEndExcluding": "4.19.323" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.4.285" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.10.227" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.15.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.1.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.6.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.10.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.11.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.12" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a9bdd5b36887d2bacb8bc777fd18317c99fc2587" }, { "url": "https://git.kernel.org/stable/c/bc2140534b2aae752e4f7cb4489642dbb5ec4777" }, { "url": "https://git.kernel.org/stable/c/e1277ae780cca4e69ef5468d4582dfd48f0b8320" }, { "url": "https://git.kernel.org/stable/c/8aa9de02a4be2e7006e636816ce19b0d667ceaa3" }, { "url": "https://git.kernel.org/stable/c/ddbdaad123254fb53e32480cb74a486a6868b1e0" }, { "url": "https://git.kernel.org/stable/c/7faed2896d78e48ec96229e73b30b0af6c00a9aa" }, { "url": "https://git.kernel.org/stable/c/880692ee233ba63808182705b3333403413b58f5" }, { "url": "https://git.kernel.org/stable/c/6d130db286ad0ea392c96ebb2551acf0d7308048" }, { "url": "https://git.kernel.org/stable/c/18ad4df091dd5d067d2faa8fce1180b79f7041a7" } ], "title": "block, bfq: fix possible UAF for bfqq->bic with merge chain", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-47706", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-10-21T13:03:53.838190Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-10-21T13:04:19.673Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T22:21:10.318Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T11:58:28.698Z" }, "affected": [ { "vendor": "Siemens", "product": "RUGGEDCOM RST2428P", "versions": [ { "status": "affected", "version": "0", "lessThan": "V3.2", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family", "versions": [ { "status": "affected", "version": "0", "lessThan": "V3.2", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SCALANCE XCM-/XRM-/XCH-/XRH-300 family", "versions": [ { "status": "affected", "version": "0", "lessThan": "V3.2", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html" }, { "url": "https://cert-portal.siemens.com/productcert/html/ssa-355557.html" } ] } ] } }