{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-40925", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-07-12T12:17:45.582Z", "datePublished": "2024-07-12T12:25:05.747Z", "dateUpdated": "2026-08-05T11:34:04.175Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:34:04.175Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: fix request.queuelist usage in flush\n\nFriedrich Weber reported a kernel crash problem and bisected to commit\n81ada09cc25e (\"blk-flush: reuse rq queuelist in flush state machine\").\n\nThe root cause is that we use \"list_move_tail(&rq->queuelist, pending)\"\nin the PREFLUSH/POSTFLUSH sequences. But rq->queuelist.next == xxx since\nit's popped out from plug->cached_rq in __blk_mq_alloc_requests_batch().\nWe don't initialize its queuelist just for this first request, although\nthe queuelist of all later popped requests will be initialized.\n\nFix it by changing to use \"list_add_tail(&rq->queuelist, pending)\" so\nrq->queuelist doesn't need to be initialized. It should be ok since rq\ncan't be on any list when PREFLUSH or POSTFLUSH, has no move actually.\n\nPlease note the commit 81ada09cc25e (\"blk-flush: reuse rq queuelist in\nflush state machine\") also has another requirement that no drivers would\ntouch rq->queuelist after blk_mq_end_request() since we will reuse it to\nadd rq to the post-flush pending list in POSTFLUSH. If this is not true,\nwe will have to revert that commit IMHO.\n\nThis updated version adds \"list_del_init(&rq->queuelist)\" in flush rq\ncallback since the dm layer may submit request of a weird invalid format\n(REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH), which causes double list_add\nif without this \"list_del_init(&rq->queuelist)\". The weird invalid format\nproblem should be fixed in dm layer." } ], "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 vulnerable path is reached only through local I/O submission — `io_uring_enter(2)` with a multi-SQE batch is the sole caller of `blk_start_plug_nr_ios()`, which is what enables the batched request allocation that leaves `rq->queuelist` uninitialized. No network protocol handler reaches `blk_mq_get_new_requests()` with `plug->nr_ios > 1`.\nAC:L - No race is involved: the attacker deterministically controls both the io_uring batch size (making `plug->nr_ios > 1`) and the ordering that puts a flush/FUA bio first in the plug, and write-cache-without-FUA queues (dm/LVM, virtio-blk, SATA/SCSI) are the common default. Tag pressure needed to force the NULL-`next` variant is also attacker-generated by keeping the device queue busy.\nPR:L - Any unprivileged local user with io_uring available (default on mainline) and a writable file or block-backed filesystem can submit the required batch; no capability, CAP_SYS_ADMIN, or device-management privilege is needed. A confined container user with a dm-backed overlay qualifies equally.\nUI:N - The attacker triggers the corrupted `list_move_tail()` entirely from their own io_uring submissions; no victim action, mount, or administrator step is required.\nS:U - The corruption and its consequences stay within the host kernel's own security authority — kernel heap/list state and block-layer request structures. No hypervisor, IOMMU, or sandbox boundary is crossed by the defect itself.\nC:H - This is real memory corruption, not a bare NULL dereference: `__list_del()` writes a kernel address into a stale `struct request`, and the double-`list_add` on the flush pending list can truncate or loop that list so `flush_end_io()`/`blk_kick_flush()` dereference and re-process requests that have already been ended, yielding use-after-free reads of request/tag state and cross-I/O data exposure into user buffers.\nI:H - The bug gives an uncontrolled kernel-pointer store (`next->prev = prev`) into a stale `struct request` plus corruption of the flush pending list, which can drive `blk_mq_end_request()` on an already-completed request — a tag double-free and request reuse, i.e. a use-after-free primitive over block-layer objects with attacker-influenced heap contents and on-disk data written to the wrong request.\nA:H - The originally reported symptom is a kernel crash: the NULL-`next` variant faults at address 0x8 while holding `fq->mq_flush_lock` with interrupts disabled, and the list-corruption variant orphans pending flush requests so their submitters hang in D state forever with tags never released, stalling the whole device queue." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/blk-flush.c" ], "versions": [ { "version": "81ada09cc25e4bf2de7d2951925fb409338a545d", "lessThan": "fe1e395563ccb051e9dbd8fa99859f5caaad2e71", "status": "affected", "versionType": "git" }, { "version": "81ada09cc25e4bf2de7d2951925fb409338a545d", "lessThan": "87907bd69721a8506618a954d41a1de3040e88aa", "status": "affected", "versionType": "git" }, { "version": "81ada09cc25e4bf2de7d2951925fb409338a545d", "lessThan": "d0321c812d89c5910d8da8e4b10c891c6b96ff70", "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/blk-flush.c" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.35", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.9.6", "lessThanOrEqual": "6.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.10", "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": "6.6", "versionEndExcluding": "6.6.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.9.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.10" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fe1e395563ccb051e9dbd8fa99859f5caaad2e71" }, { "url": "https://git.kernel.org/stable/c/87907bd69721a8506618a954d41a1de3040e88aa" }, { "url": "https://git.kernel.org/stable/c/d0321c812d89c5910d8da8e4b10c891c6b96ff70" } ], "title": "block: fix request.queuelist usage in flush", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-02T04:39:56.086Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/fe1e395563ccb051e9dbd8fa99859f5caaad2e71", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/87907bd69721a8506618a954d41a1de3040e88aa", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/d0321c812d89c5910d8da8e4b10c891c6b96ff70", "tags": [ "x_transferred" ] } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-40925", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T17:05:17.851843Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-11T17:33:03.370Z" } } ] } }