{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-49855", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-10-21T12:17:06.016Z", "datePublished": "2024-10-21T12:18:47.391Z", "dateUpdated": "2026-08-05T11:40:05.597Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:40:05.597Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: fix race between timeout and normal completion\n\nIf request timetout is handled by nbd_requeue_cmd(), normal completion\nhas to be stopped for avoiding to complete this requeued request, other\nuse-after-free can be triggered.\n\nFix the race by clearing NBD_CMD_INFLIGHT in nbd_requeue_cmd(), meantime\nmake sure that cmd->lock is grabbed for clearing the flag and the\nrequeue." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The race is driven by the NBD reply stream received over TCP in `recv_work()`/`nbd_handle_reply()`, code that processes data from a remote peer; a malicious or compromised NBD server — or an on-path attacker, since the NBD protocol is plaintext and unauthenticated on port 10809 — controls reply timing and content.\nAC:L - The remote server controls both sides of the race: it withholds a reply to force `nbd_xmit_timeout()` to fire, then delivers the reply at that instant to collide with `nbd_requeue_cmd()`, and it can repeat this across many in-flight requests indefinitely at no cost.\nPR:N - The NBD protocol carries no authentication, so the attacking server or MITM needs no credentials or privileges on the victim host; the CAP_SYS_ADMIN gate only covers the victim admin's own legitimate `nbd-client` setup, which is a pre-existing deployment condition rather than an attacker privilege.\nUI:N - No victim action is needed at attack time — an already-established NBD session (diskless boot, cloud block storage) is enough, and a compromised server or on-path attacker triggers the race unilaterally.\nS:U - The use-after-free and block-layer corruption stay within the kernel of the affected host; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Re-dispatching an already-completed request makes `nbd_send_cmd()` walk freed bio/bvec memory and transmit its contents over the socket to the attacker-controlled server, directly disclosing freed kernel/page-cache data.\nI:H - A re-dispatched READ writes the server's attacker-chosen reply payload into freed and possibly reallocated pages, and the requeue of a reused request corrupts `q->requeue_list`/`rq->queuelist` — a controlled write primitive usable for control-flow hijacking.\nA:H - The double completion and requeue of a freed/reused request reliably produce list corruption, KASAN use-after-free splats, oops, or hang of the storage path and the machine." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/block/nbd.c" ], "versions": [ { "version": "2895f1831e911ca87d4efdf43e35eb72a0c7e66e", "lessThan": "9c25faf72d780a9c71081710cd48759d61ff6e9b", "status": "affected", "versionType": "git" }, { "version": "2895f1831e911ca87d4efdf43e35eb72a0c7e66e", "lessThan": "6e73b946a379a1dfbb62626af93843bdfb53753d", "status": "affected", "versionType": "git" }, { "version": "2895f1831e911ca87d4efdf43e35eb72a0c7e66e", "lessThan": "5236ada8ebbd9e7461f17477357582f5be4f46f7", "status": "affected", "versionType": "git" }, { "version": "2895f1831e911ca87d4efdf43e35eb72a0c7e66e", "lessThan": "9a74c3e6c0d686c26ba2aab66d15ddb89dc139cc", "status": "affected", "versionType": "git" }, { "version": "2895f1831e911ca87d4efdf43e35eb72a0c7e66e", "lessThan": "c9ea57c91f03bcad415e1a20113bdb2077bcf990", "status": "affected", "versionType": "git" }, { "version": "cdf62c535a9bfd5ff0eef4b91669da39d8abc0c3", "status": "affected", "versionType": "git" }, { "version": "5171ef20bae852ff38f4cfdb368bcdcc744776d0", "status": "affected", "versionType": "git" }, { "version": "5.17.15", "lessThan": "5.18", "status": "affected", "versionType": "semver" }, { "version": "5.18.4", "lessThan": "5.19", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/block/nbd.c" ], "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "lessThan": "5.19", "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": "5.19", "versionEndExcluding": "6.1.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.6.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.10.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.11.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17.15" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9c25faf72d780a9c71081710cd48759d61ff6e9b" }, { "url": "https://git.kernel.org/stable/c/6e73b946a379a1dfbb62626af93843bdfb53753d" }, { "url": "https://git.kernel.org/stable/c/5236ada8ebbd9e7461f17477357582f5be4f46f7" }, { "url": "https://git.kernel.org/stable/c/9a74c3e6c0d686c26ba2aab66d15ddb89dc139cc" }, { "url": "https://git.kernel.org/stable/c/c9ea57c91f03bcad415e1a20113bdb2077bcf990" } ], "title": "nbd: fix race between timeout and normal completion", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-49855", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-10-21T12:56:24.992815Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-10-21T13:04:11.227Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T22:22:24.136Z" } } ] } }