CVE-2024-56693 (GCVE-0-2024-56693)
Vulnerability from cvelistv5 – Published: 2024-12-28 09:46 – Updated: 2026-08-05 11:46
VLAI
EPSS
VEX
Title
brd: defer automatic disk creation until module initialization succeeds
Summary
In the Linux kernel, the following vulnerability has been resolved:
brd: defer automatic disk creation until module initialization succeeds
My colleague Wupeng found the following problems during fault injection:
BUG: unable to handle page fault for address: fffffbfff809d073
PGD 6e648067 P4D 123ec8067 PUD 123ec4067 PMD 100e38067 PTE 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 5 UID: 0 PID: 755 Comm: modprobe Not tainted 6.12.0-rc3+ #17
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.1-2.fc37 04/01/2014
RIP: 0010:__asan_load8+0x4c/0xa0
...
Call Trace:
<TASK>
blkdev_put_whole+0x41/0x70
bdev_release+0x1a3/0x250
blkdev_release+0x11/0x20
__fput+0x1d7/0x4a0
task_work_run+0xfc/0x180
syscall_exit_to_user_mode+0x1de/0x1f0
do_syscall_64+0x6b/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
loop_init() is calling loop_add() after __register_blkdev() succeeds and
is ignoring disk_add() failure from loop_add(), for loop_add() failure
is not fatal and successfully created disks are already visible to
bdev_open().
brd_init() is currently calling brd_alloc() before __register_blkdev()
succeeds and is releasing successfully created disks when brd_init()
returns an error. This can cause UAF for the latter two case:
case 1:
T1:
modprobe brd
brd_init
brd_alloc(0) // success
add_disk
disk_scan_partitions
bdev_file_open_by_dev // alloc file
fput // won't free until back to userspace
brd_alloc(1) // failed since mem alloc error inject
// error path for modprobe will release code segment
// back to userspace
__fput
blkdev_release
bdev_release
blkdev_put_whole
bdev->bd_disk->fops->release // fops is freed now, UAF!
case 2:
T1: T2:
modprobe brd
brd_init
brd_alloc(0) // success
open(/dev/ram0)
brd_alloc(1) // fail
// error path for modprobe
close(/dev/ram0)
...
/* UAF! */
bdev->bd_disk->fops->release
Fix this problem by following what loop_init() does. Besides,
reintroduce brd_devices_mutex to help serialize modifications to
brd_list.
Severity
7.8 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-02-10 17:12 UTC
CWE
- CWE-416 - Use After Free
Assigner
References
7 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
7f9b348cb5e94259acdcbafbcaed55d3bb515304 , < 41219c147df8bbd6591f59af5d695fb6c9a1cbff
(git)
Affected: 7f9b348cb5e94259acdcbafbcaed55d3bb515304 , < 259bf925583ec9e3781df778cadf00594095090d (git) Affected: 7f9b348cb5e94259acdcbafbcaed55d3bb515304 , < 410896624db639500f24f46478b4bfa05c76bf56 (git) Affected: 7f9b348cb5e94259acdcbafbcaed55d3bb515304 , < c0c2744cd2939ec5999c51dbaf2af16886548b7b (git) Affected: 7f9b348cb5e94259acdcbafbcaed55d3bb515304 , < 63dfd728b30f79495dacc886127695a379805152 (git) Affected: 7f9b348cb5e94259acdcbafbcaed55d3bb515304 , < 826cc42adf44930a633d11a5993676d85ddb0842 (git) |
guessed | |
| Linux | Linux |
Affected:
5.14
Unaffected: 0 , < 5.14 (semver) Unaffected: 5.15.174 , ≤ 5.15.* (semver) Unaffected: 6.1.120 , ≤ 6.1.* (semver) Unaffected: 6.6.64 , ≤ 6.6.* (semver) Unaffected: 6.11.11 , ≤ 6.11.* (semver) Unaffected: 6.12.2 , ≤ 6.12.* (semver) Unaffected: 6.13 , ≤ * (original_commit_for_fix) |
guessed |
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"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 \u003cTASK\u003e\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\u0027t 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-\u003ebd_disk-\u003efops-\u003erelease // 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-\u003ebd_disk-\u003efops-\u003erelease\n\nFix this problem by following what loop_init() does. Besides,\nreintroduce brd_devices_mutex to help serialize modifications to\nbrd_list."
}
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"value": "AV:L - Triggering requires local access \u2014 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 \u2014 the attacker\u0027s 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-\u003efops dangles into freed module memory and disk-\u003eprivate_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() \u2192 bdev_release() path), and any use-after-free of this kind reliably panics the machine."
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"datePublished": "2024-12-28T09:46:18.203Z",
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"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 \u003cTASK\u003e\\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\u0027t 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-\u003ebd_disk-\u003efops-\u003erelease // 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-\u003ebd_disk-\u003efops-\u003erelease\\n\\nFix this problem by following what loop_init() does. Besides,\\nreintroduce brd_devices_mutex to help serialize modifications to\\nbrd_list.\"}, {\"lang\": \"es\", \"value\": \"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: brd: aplazar la creaci\\u00f3n autom\\u00e1tica de discos hasta que la inicializaci\\u00f3n del m\\u00f3dulo tenga \\u00e9xito. Mi colega Wupeng encontr\\u00f3 los siguientes problemas durante la inyecci\\u00f3n de fallas: ERROR: no se puede gestionar la falla de p\\u00e1gina para la direcci\\u00f3n: fffffbfff809d073 PGD 6e648067 P4D 123ec8067 PUD 123ec4067 PMD 100e38067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 5 UID: 0 PID: 755 Comm: modprobe No contaminado 6.12.0-rc3+ #17 Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:__asan_load8+0x4c/0xa0 ... Seguimiento de llamadas: blkdev_put_whole+0x41/0x70 bdev_release+0x1a3/0x250 blkdev_release+0x11/0x20 __fput+0x1d7/0x4a0 task_work_run+0xfc/0x180 syscall_exit_to_user_mode+0x1de/0x1f0 do_syscall_64+0x6b/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e loop_init() est\\u00e1 llamando a loop_add() despu\\u00e9s de que __register_blkdev() tenga \\u00e9xito e ignora el error de disk_add() de loop_add(), ya que el error de loop_add() no es fatal y los discos creados correctamente ya est\\u00e1n visibles para bdev_open().brd_init() actualmente est\\u00e1 llamando a brd_alloc() antes de que __register_blkdev() tenga \\u00e9xito y est\\u00e1 liberando discos creados exitosamente cuando brd_init() devuelve un error. Esto puede causar UAF para los \\u00faltimos dos casos: caso 1: T1: modprobe brd brd_init brd_alloc(0) // \\u00e9xito add_disk disk_scan_partitions bdev_file_open_by_dev // asignar archivo fput // no se liberar\\u00e1 hasta que regrese al espacio de usuario brd_alloc(1) // fall\\u00f3 debido a un error de asignaci\\u00f3n de memoria inject // error la ruta para modprobe liberar\\u00e1 el segmento de c\\u00f3digo // de regreso al espacio de usuario __fput blkdev_release bdev_release blkdev_put_whole bdev-\u0026gt;bd_disk-\u0026gt;fops-\u0026gt;release // fops est\\u00e1 liberado ahora, \\u00a1UAF! caso 2: T1: T2: modprobe brd brd_init brd_alloc(0) // \\u00e9xito open(/dev/ram0) brd_alloc(1) // error // ruta de error para modprobe close(/dev/ram0) ... /* UAF! */ bdev-\u0026gt;bd_disk-\u0026gt;fops-\u0026gt;release Solucione este problema siguiendo lo que hace loop_init(). Adem\\u00e1s, vuelva a introducir brd_devices_mutex para ayudar a serializar las modificaciones a brd_list.\"}]",
"id": "CVE-2024-56693",
"lastModified": "2024-12-28T10:15:14.833",
"published": "2024-12-28T10:15:14.833",
"references": "[{\"url\": \"https://git.kernel.org/stable/c/259bf925583ec9e3781df778cadf00594095090d\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/410896624db639500f24f46478b4bfa05c76bf56\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/41219c147df8bbd6591f59af5d695fb6c9a1cbff\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/63dfd728b30f79495dacc886127695a379805152\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/826cc42adf44930a633d11a5993676d85ddb0842\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/c0c2744cd2939ec5999c51dbaf2af16886548b7b\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2024-56693\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-12-28T10:15:14.833\",\"lastModified\":\"2026-06-17T08:12:45.590\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"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 \u003cTASK\u003e\\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\u0027t 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-\u003ebd_disk-\u003efops-\u003erelease // 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-\u003ebd_disk-\u003efops-\u003erelease\\n\\nFix this problem by following what loop_init() does. Besides,\\nreintroduce brd_devices_mutex to help serialize modifications to\\nbrd_list.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: brd: aplazar la creaci\u00f3n autom\u00e1tica de discos hasta que la inicializaci\u00f3n del m\u00f3dulo tenga \u00e9xito. Mi colega Wupeng encontr\u00f3 los siguientes problemas durante la inyecci\u00f3n de fallas: ERROR: no se puede gestionar la falla de p\u00e1gina para la direcci\u00f3n: fffffbfff809d073 PGD 6e648067 P4D 123ec8067 PUD 123ec4067 PMD 100e38067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 5 UID: 0 PID: 755 Comm: modprobe No contaminado 6.12.0-rc3+ #17 Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:__asan_load8+0x4c/0xa0 ... Seguimiento de llamadas: blkdev_put_whole+0x41/0x70 bdev_release+0x1a3/0x250 blkdev_release+0x11/0x20 __fput+0x1d7/0x4a0 task_work_run+0xfc/0x180 syscall_exit_to_user_mode+0x1de/0x1f0 do_syscall_64+0x6b/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e loop_init() est\u00e1 llamando a loop_add() despu\u00e9s de que __register_blkdev() tenga \u00e9xito e ignora el error de disk_add() de loop_add(), ya que el error de loop_add() no es fatal y los discos creados correctamente ya est\u00e1n visibles para bdev_open().brd_init() actualmente est\u00e1 llamando a brd_alloc() antes de que __register_blkdev() tenga \u00e9xito y est\u00e1 liberando discos creados exitosamente cuando brd_init() devuelve un error. Esto puede causar UAF para los \u00faltimos dos casos: caso 1: T1: modprobe brd brd_init brd_alloc(0) // \u00e9xito add_disk disk_scan_partitions bdev_file_open_by_dev // asignar archivo fput // no se liberar\u00e1 hasta que regrese al espacio de usuario brd_alloc(1) // fall\u00f3 debido a un error de asignaci\u00f3n de memoria inject // error la ruta para modprobe liberar\u00e1 el segmento de c\u00f3digo // de regreso al espacio de usuario __fput blkdev_release bdev_release blkdev_put_whole bdev-\u0026gt;bd_disk-\u0026gt;fops-\u0026gt;release // fops est\u00e1 liberado ahora, \u00a1UAF! caso 2: T1: T2: modprobe brd brd_init brd_alloc(0) // \u00e9xito open(/dev/ram0) brd_alloc(1) // error // ruta de error para modprobe close(/dev/ram0) ... /* UAF! */ bdev-\u0026gt;bd_disk-\u0026gt;fops-\u0026gt;release Solucione este problema siguiendo lo que hace loop_init(). Adem\u00e1s, vuelva a introducir brd_devices_mutex para ayudar a serializar las modificaciones a brd_list.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/block/brd.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7f9b348cb5e94259acdcbafbcaed55d3bb515304\",\"lessThan\":\"41219c147df8bbd6591f59af5d695fb6c9a1cbff\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7f9b348cb5e94259acdcbafbcaed55d3bb515304\",\"lessThan\":\"259bf925583ec9e3781df778cadf00594095090d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7f9b348cb5e94259acdcbafbcaed55d3bb515304\",\"lessThan\":\"410896624db639500f24f46478b4bfa05c76bf56\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7f9b348cb5e94259acdcbafbcaed55d3bb515304\",\"lessThan\":\"c0c2744cd2939ec5999c51dbaf2af16886548b7b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7f9b348cb5e94259acdcbafbcaed55d3bb515304\",\"lessThan\":\"63dfd728b30f79495dacc886127695a379805152\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7f9b348cb5e94259acdcbafbcaed55d3bb515304\",\"lessThan\":\"826cc42adf44930a633d11a5993676d85ddb0842\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/block/brd.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.14\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.14\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.174\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.120\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.64\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.11.11\",\"lessThanOrEqual\":\"6.11.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.2\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.13\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"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\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2025-02-10T17:12:21.851341Z\",\"id\":\"CVE-2024-56693\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA 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"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-06-28T08:17:07+00:00",
"cve": "CVE-2024-56693",
"id": "CVE-2024-56693",
"initial_release_date": "2024-12-28T00:00:00+00:00",
"product_status:fixed": "305",
"product_status:known_affected": "64",
"product_status:known_not_affected": "48",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: brd: defer automatic disk creation until module initialization succeeds",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-56693.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "important",
"current_release_date": "2026-09-16T00:20:46Z",
"cve": "CVE-2024-56693",
"id": "CVE-2024-56693",
"initial_release_date": "2024-12-29T03:48:08Z",
"product_status:known_affected": "410",
"product_status:known_not_affected": "321",
"product_status:recommended": "401",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2024-56693",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2024-56693.json",
"version": "131"
},
"vulnrichment": {
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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 \\u2014 the attacker\u0027s 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-\u003efops dangles into freed module memory and disk-\u003eprivate_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() \\u2192 bdev_release() path), and any use-after-free of this kind reliably panics the machine.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"7f9b348cb5e94259acdcbafbcaed55d3bb515304\", \"lessThan\": \"41219c147df8bbd6591f59af5d695fb6c9a1cbff\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"7f9b348cb5e94259acdcbafbcaed55d3bb515304\", \"lessThan\": \"259bf925583ec9e3781df778cadf00594095090d\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"7f9b348cb5e94259acdcbafbcaed55d3bb515304\", \"lessThan\": \"410896624db639500f24f46478b4bfa05c76bf56\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"7f9b348cb5e94259acdcbafbcaed55d3bb515304\", \"lessThan\": \"c0c2744cd2939ec5999c51dbaf2af16886548b7b\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"7f9b348cb5e94259acdcbafbcaed55d3bb515304\", \"lessThan\": \"63dfd728b30f79495dacc886127695a379805152\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"7f9b348cb5e94259acdcbafbcaed55d3bb515304\", \"lessThan\": \"826cc42adf44930a633d11a5993676d85ddb0842\", \"versionType\": \"git\"}], \"programFiles\": [\"drivers/block/brd.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.14\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.14\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.15.174\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"6.1.120\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.64\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.11.11\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.11.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.2\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.13\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"drivers/block/brd.c\"], \"defaultStatus\": \"affected\"}], \"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\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"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 \u003cTASK\u003e\\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\u0027t 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-\u003ebd_disk-\u003efops-\u003erelease // 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-\u003ebd_disk-\u003efops-\u003erelease\\n\\nFix this problem by following what loop_init() does. Besides,\\nreintroduce brd_devices_mutex to help serialize modifications to\\nbrd_list.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.174\", \"versionStartIncluding\": \"5.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.120\", \"versionStartIncluding\": \"5.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.64\", \"versionStartIncluding\": \"5.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.11.11\", \"versionStartIncluding\": \"5.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.2\", \"versionStartIncluding\": \"5.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.13\", \"versionStartIncluding\": \"5.14\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T11:46:07.115Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2024-56693\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T11:46:07.115Z\", \"dateReserved\": \"2024-12-27T15:00:39.849Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-12-28T09:46:18.203Z\", \"assignerShortName\": \"Linux\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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