CVE-2021-47638
Estado: ModificadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
ubifs: rename_whiteout: Fix double free for whiteout_ui->data
'whiteout_ui->data' will be freed twice if space budget fail for rename whiteout operation as following process:
The buggy address belongs to the object at ffff88810238bed8 which belongs to the cache kmalloc-8 of size 8 ==================================================================
Let ubifs_free_inode() free 'whiteout_ui->data'. BTW, delete unused assignment 'whiteout_ui->data_len = 0', process 'ubifs_evict_inode() -> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' doesn't need it (because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release', and the nlink of whiteout inode is 0).
Detalles técnicos trazas, registros y código del informe original
rename_whiteout
dev = kmalloc
whiteout_ui->data = dev
kfree(whiteout_ui->data) // Free first time
iput(whiteout)
ubifs_free_inode
kfree(ui->data) // Double free!
KASAN reports:
==================================================================
BUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70
Call Trace:
kfree+0x117/0x490
ubifs_free_inode+0x4f/0x70 [ubifs]
i_callback+0x30/0x60
rcu_do_batch+0x366/0xac0
__do_softirq+0x133/0x57f
Allocated by task 1506:
kmem_cache_alloc_trace+0x3c2/0x7a0
do_rename+0x9b7/0x1150 [ubifs]
ubifs_rename+0x106/0x1f0 [ubifs]
do_syscall_64+0x35/0x80
Freed by task 1506:
kfree+0x117/0x490
do_rename.cold+0x53/0x8a [ubifs]
ubifs_rename+0x106/0x1f0 [ubifs]
do_syscall_64+0x35/0x80CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.26%
- Percentil entre todas las CVEs puntuadas: 16
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-415
- CWE-415
Referencias
- https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc
- https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742
- https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa
- https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e
- https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd
- https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274
- https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8
- https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f
JSON original (NVD)
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: rename_whiteout: Fix double free for whiteout_ui->data\n\n'whiteout_ui->data' will be freed twice if space budget fail for\nrename whiteout operation as following process:\n\nrename_whiteout\n dev = kmalloc\n whiteout_ui->data = dev\n kfree(whiteout_ui->data) // Free first time\n iput(whiteout)\n ubifs_free_inode\n kfree(ui->data)\t // Double free!\n\nKASAN reports:\n==================================================================\nBUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70\nCall Trace:\n kfree+0x117/0x490\n ubifs_free_inode+0x4f/0x70 [ubifs]\n i_callback+0x30/0x60\n rcu_do_batch+0x366/0xac0\n __do_softirq+0x133/0x57f\n\nAllocated by task 1506:\n kmem_cache_alloc_trace+0x3c2/0x7a0\n do_rename+0x9b7/0x1150 [ubifs]\n ubifs_rename+0x106/0x1f0 [ubifs]\n do_syscall_64+0x35/0x80\n\nFreed by task 1506:\n kfree+0x117/0x490\n do_rename.cold+0x53/0x8a [ubifs]\n ubifs_rename+0x106/0x1f0 [ubifs]\n do_syscall_64+0x35/0x80\n\nThe buggy address belongs to the object at ffff88810238bed8 which\nbelongs to the cache kmalloc-8 of size 8\n==================================================================\n\nLet ubifs_free_inode() free 'whiteout_ui->data'. BTW, delete unused\nassignment 'whiteout_ui->data_len = 0', process 'ubifs_evict_inode()\n-> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' doesn't need it\n(because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release',\n and the nlink of whiteout inode is 0)."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ubifs: rename_whiteout: Se corrige la doble liberación para whiteout_ui->data 'whiteout_ui->data' se liberará dos veces si el presupuesto de espacio falla para la operación de cambio de nombre de whiteout como el siguiente proceso: rename_whiteout dev = kmalloc whiteout_ui->data = dev kfree(whiteout_ui->data) // Libera la primera vez iput(whiteout) ubifs_free_inode kfree(ui->data) // ¡Doble liberación! KASAN informa: ==================================================================== ERROR: KASAN: liberación doble o liberación no válida en ubifs_free_inode+0x4f/0x70 Seguimiento de llamadas: kfree+0x117/0x490 ubifs_free_inode+0x4f/0x70 [ubifs] i_callback+0x30/0x60 rcu_do_batch+0x366/0xac0 __do_softirq+0x133/0x57f Asignado por la tarea 1506: kmem_cache_alloc_trace+0x3c2/0x7a0 do_rename+0x9b7/0x1150 [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 Liberado por la tarea 1506: kfree+0x117/0x490 do_rename.cold+0x53/0x8a [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 La dirección con errores pertenece al objeto en ffff88810238bed8 que pertenece al caché kmalloc-8 de tamaño 8 ===================================================================== Deje que ubifs_free_inode() libere 'whiteout_ui->data'. Por cierto, elimine la asignación no utilizada 'whiteout_ui->data_len = 0', el proceso 'ubifs_evict_inode() -> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' no lo necesita (porque 'inc_nlink(whiteout)' no será ejecutado por 'goto out_release', y el nlink del inodo whiteout es 0)."
}
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"lastModified": "2026-08-04T10:17:11.823",
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