CVE-2026-31654
Estado: AnalizadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
mm/vma: fix memory leak in __mmap_region()
commit 605f6586ecf7 ("mm/vma: do not leak memory when .mmap_prepare swaps the file") handled the success path by skipping get_file() via file_doesnt_need_get, but missed the error path.
When /dev/zero is mmap'd with MAP_SHARED, mmap_zero_prepare() calls shmem_zero_setup_desc() which allocates a new shmem file to back the mapping. If __mmap_new_vma() subsequently fails, this replacement file is never fput()'d - the original is released by ksys_mmap_pgoff(), but nobody releases the new one.
Leer descripción completaMostrar menos
Add fput() for the swapped file in the error path.
Reproducible with fault injection.
Found by syzkaller.
Detalles técnicos trazas, registros y código del informe original
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 1
CPU: 2 UID: 0 PID: 366 Comm: syz.7.14 Not tainted 7.0.0-rc6 #2 PREEMPT(full)
Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x164/0x1f0
should_fail_ex+0x525/0x650
should_failslab+0xdf/0x140
kmem_cache_alloc_noprof+0x78/0x630
vm_area_alloc+0x24/0x160
__mmap_region+0xf6b/0x2660
mmap_region+0x2eb/0x3a0
do_mmap+0xc79/0x1240
vm_mmap_pgoff+0x252/0x4c0
ksys_mmap_pgoff+0xf8/0x120
__x64_sys_mmap+0x12a/0x190
do_syscall_64+0xa9/0x580
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
BUG: memory leak
unreferenced object 0xffff8881118aca80 (size 360):
comm "syz.7.14", pid 366, jiffies 4294913255
hex dump (first 32 bytes):
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N..........
ff ff ff ff ff ff ff ff c0 28 4d ae ff ff ff ff .........(M.....
backtrace (crc db0f53bc):
kmem_cache_alloc_noprof+0x3ab/0x630
alloc_empty_file+0x5a/0x1e0
alloc_file_pseudo+0x135/0x220
__shmem_file_setup+0x274/0x420
shmem_zero_setup_desc+0x9c/0x170
mmap_zero_prepare+0x123/0x140
__mmap_region+0xdda/0x2660
mmap_region+0x2eb/0x3a0
do_mmap+0xc79/0x1240
vm_mmap_pgoff+0x252/0x4c0
ksys_mmap_pgoff+0xf8/0x120
__x64_sys_mmap+0x12a/0x190
do_syscall_64+0xa9/0x580
entry_SYSCALL_64_after_hwframe+0x76/0x7eCVSS
- 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: 0.16%
- Percentil entre todas las CVEs puntuadas: 5
- 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-401
Referencias
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vma: fix memory leak in __mmap_region()\n\ncommit 605f6586ecf7 (\"mm/vma: do not leak memory when .mmap_prepare\nswaps the file\") handled the success path by skipping get_file() via\nfile_doesnt_need_get, but missed the error path.\n\nWhen /dev/zero is mmap'd with MAP_SHARED, mmap_zero_prepare() calls\nshmem_zero_setup_desc() which allocates a new shmem file to back the\nmapping. If __mmap_new_vma() subsequently fails, this replacement\nfile is never fput()'d - the original is released by\nksys_mmap_pgoff(), but nobody releases the new one.\n\nAdd fput() for the swapped file in the error path.\n\nReproducible with fault injection.\n\nFAULT_INJECTION: forcing a failure.\nname failslab, interval 1, probability 0, space 0, times 1\nCPU: 2 UID: 0 PID: 366 Comm: syz.7.14 Not tainted 7.0.0-rc6 #2 PREEMPT(full)\nHardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nCall Trace:\n <TASK>\n dump_stack_lvl+0x164/0x1f0\n should_fail_ex+0x525/0x650\n should_failslab+0xdf/0x140\n kmem_cache_alloc_noprof+0x78/0x630\n vm_area_alloc+0x24/0x160\n __mmap_region+0xf6b/0x2660\n mmap_region+0x2eb/0x3a0\n do_mmap+0xc79/0x1240\n vm_mmap_pgoff+0x252/0x4c0\n ksys_mmap_pgoff+0xf8/0x120\n __x64_sys_mmap+0x12a/0x190\n do_syscall_64+0xa9/0x580\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n </TASK>\n\nkmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)\nBUG: memory leak\nunreferenced object 0xffff8881118aca80 (size 360):\n comm \"syz.7.14\", pid 366, jiffies 4294913255\n hex dump (first 32 bytes):\n 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N..........\n ff ff ff ff ff ff ff ff c0 28 4d ae ff ff ff ff .........(M.....\n backtrace (crc db0f53bc):\n kmem_cache_alloc_noprof+0x3ab/0x630\n alloc_empty_file+0x5a/0x1e0\n alloc_file_pseudo+0x135/0x220\n __shmem_file_setup+0x274/0x420\n shmem_zero_setup_desc+0x9c/0x170\n mmap_zero_prepare+0x123/0x140\n __mmap_region+0xdda/0x2660\n mmap_region+0x2eb/0x3a0\n do_mmap+0xc79/0x1240\n vm_mmap_pgoff+0x252/0x4c0\n ksys_mmap_pgoff+0xf8/0x120\n __x64_sys_mmap+0x12a/0x190\n do_syscall_64+0xa9/0x580\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFound by syzkaller."
}
],
"lastModified": "2026-06-17T10:34:10.353",
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