{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-56693", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-27T15:00:39.849Z", "datePublished": "2024-12-28T09:46:18.203Z", "dateUpdated": "2026-08-05T11:46:07.115Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:46:07.115Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbrd: defer automatic disk creation until module initialization succeeds\n\nMy colleague Wupeng found the following problems during fault injection:\n\nBUG: unable to handle page fault for address: fffffbfff809d073\nPGD 6e648067 P4D 123ec8067 PUD 123ec4067 PMD 100e38067 PTE 0\nOops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI\nCPU: 5 UID: 0 PID: 755 Comm: modprobe Not tainted 6.12.0-rc3+ #17\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n1.16.1-2.fc37 04/01/2014\nRIP: 0010:__asan_load8+0x4c/0xa0\n...\nCall Trace:\n \n blkdev_put_whole+0x41/0x70\n bdev_release+0x1a3/0x250\n blkdev_release+0x11/0x20\n __fput+0x1d7/0x4a0\n task_work_run+0xfc/0x180\n syscall_exit_to_user_mode+0x1de/0x1f0\n do_syscall_64+0x6b/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nloop_init() is calling loop_add() after __register_blkdev() succeeds and\nis ignoring disk_add() failure from loop_add(), for loop_add() failure\nis not fatal and successfully created disks are already visible to\nbdev_open().\n\nbrd_init() is currently calling brd_alloc() before __register_blkdev()\nsucceeds and is releasing successfully created disks when brd_init()\nreturns an error. This can cause UAF for the latter two case:\n\ncase 1:\n T1:\nmodprobe brd\n brd_init\n brd_alloc(0) // success\n add_disk\n disk_scan_partitions\n bdev_file_open_by_dev // alloc file\n fput // won't free until back to userspace\n brd_alloc(1) // failed since mem alloc error inject\n // error path for modprobe will release code segment\n // back to userspace\n __fput\n blkdev_release\n bdev_release\n blkdev_put_whole\n bdev->bd_disk->fops->release // fops is freed now, UAF!\n\ncase 2:\n T1: T2:\nmodprobe brd\n brd_init\n brd_alloc(0) // success\n open(/dev/ram0)\n brd_alloc(1) // fail\n // error path for modprobe\n\n close(/dev/ram0)\n ...\n /* UAF! */\n bdev->bd_disk->fops->release\n\nFix this problem by following what loop_init() does. Besides,\nreintroduce brd_devices_mutex to help serialize modifications to\nbrd_list." } ], "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 - Triggering requires local access — loading/autoloading the brd module and holding an open file descriptor on /dev/ram0 across the failed initialization. There is no network-facing path into drivers/block/brd.c.\nAC:L - The attacker drives the exploitable side of the race directly by spinning open()/close() on /dev/ram0 (or by triggering block-major-1 autoload) and can retry unboundedly because a failed load leaves the major unregistered; the allocation failure that aborts brd_init() is inducible via local memory pressure. This matches the treatment of other allocation/registration error-path UAFs in this subsystem.\nPR:L - The attacker needs only a local account able to open the ram-disk device node (e.g. disk-group membership on stock distros, or the looser block-device permissions common on embedded/Android/appliance systems); no CAP_SYS_MODULE is needed since the module load can be an admin/boot action or kernel-initiated autoload.\nUI:N - No victim action is needed — the attacker's own open() of a major-1 node can trigger the module autoload, and the boot-time load path requires no interactive user involvement.\nS:U - The use-after-free is entirely within kernel memory and yields kernel-level compromise of the same system; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is a use-after-free: disk->fops dangles into freed module memory and disk->private_data into a freed slab object, so the attacker can reclaim those allocations and use the stale references to disclose arbitrary kernel memory.\nI:H - The dangling fops pointer results in an indirect call through freed executable module memory, which is reclaimable by subsequent module loads or BPF JIT allocations, giving a realistic control-flow-hijack/arbitrary-write primitive; the freed brd_device is likewise a heap-spray target.\nA:H - The demonstrated result is a kernel oops (unhandled page fault in blkdev_put_whole() → bdev_release() path), and any use-after-free of this kind reliably panics 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/brd.c" ], "versions": [ { "version": "7f9b348cb5e94259acdcbafbcaed55d3bb515304", "lessThan": "41219c147df8bbd6591f59af5d695fb6c9a1cbff", "status": "affected", "versionType": "git" }, { "version": "7f9b348cb5e94259acdcbafbcaed55d3bb515304", "lessThan": "259bf925583ec9e3781df778cadf00594095090d", "status": "affected", "versionType": "git" }, { "version": "7f9b348cb5e94259acdcbafbcaed55d3bb515304", "lessThan": "410896624db639500f24f46478b4bfa05c76bf56", "status": "affected", "versionType": "git" }, { "version": "7f9b348cb5e94259acdcbafbcaed55d3bb515304", "lessThan": "c0c2744cd2939ec5999c51dbaf2af16886548b7b", "status": "affected", "versionType": "git" }, { "version": "7f9b348cb5e94259acdcbafbcaed55d3bb515304", "lessThan": "63dfd728b30f79495dacc886127695a379805152", "status": "affected", "versionType": "git" }, { "version": "7f9b348cb5e94259acdcbafbcaed55d3bb515304", "lessThan": "826cc42adf44930a633d11a5993676d85ddb0842", "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/block/brd.c" ], "versions": [ { "version": "5.14", "status": "affected" }, { "version": "0", "lessThan": "5.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.174", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.120", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.64", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11.11", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.2", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13", "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": "5.14", "versionEndExcluding": "5.15.174" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.1.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.6.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.11.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.12.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/41219c147df8bbd6591f59af5d695fb6c9a1cbff" }, { "url": "https://git.kernel.org/stable/c/259bf925583ec9e3781df778cadf00594095090d" }, { "url": "https://git.kernel.org/stable/c/410896624db639500f24f46478b4bfa05c76bf56" }, { "url": "https://git.kernel.org/stable/c/c0c2744cd2939ec5999c51dbaf2af16886548b7b" }, { "url": "https://git.kernel.org/stable/c/63dfd728b30f79495dacc886127695a379805152" }, { "url": "https://git.kernel.org/stable/c/826cc42adf44930a633d11a5993676d85ddb0842" } ], "title": "brd: defer automatic disk creation until module initialization succeeds", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2024-56693", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-02-10T17:12:21.851341Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-02-10T17:21:06.885Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T20:52:41.179Z" } } ] } }