CVE-2025-39817
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: efivarfs: Fix slab-out-of-bounds in efivarfs_d_compare Observed on kernel 6.6 (present on master as well): BUG: KASAN: slab-out-of-bounds in memcmp+0x98/0xd0 Call trace: kasan_check_range+0xe8/0x190 __asan_loadN+0x1c/0x28 memcmp+0x98/0xd0 efivarfs_d_compare+0x68/0xd8 __d_lookup_rcu_op_compare+0x178/0x218 __d_lookup_rcu+0x1f8/0x228 d_alloc_parallel+0x150/0x648 lookup_open.isra.0+0x5f0/0x8d0 open_last_lookups+0x264/0x828 path_openat+0x130/0x3f8 do_filp_open+0x114/0x248 do_sys_openat2+0x340/0x3c0 __arm64_sys_openat+0x120/0x1a0 If dentry->d_name.len < EFI_VARIABLE_GUID_LEN , 'guid' can become negative, leadings to oob. The issue can be triggered by parallel lookups using invalid filename: T1 T2 lookup_open ->lookup simple_lookup d_add // invalid dentry is added to hash list lookup_open d_alloc_parallel __d_lookup_rcu __d_lookup_rcu_op_compare hlist_bl_for_each_entry_rcu // invalid dentry can be retrieved ->d_compare efivarfs_d_compare // oob Fix it by checking 'guid' before cmp.
Severity
HIGH
CVSS score
7.1
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-09-16 13:15:57.187000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON
{
"id": "CVE-2025-39817",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-09-16T13:15:57.187",
"lastModified": "2026-10-19T21:10:00.160",
"vulnStatus": "Modified",
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nefivarfs: Fix slab-out-of-bounds in efivarfs_d_compare\n\nObserved on kernel 6.6 (present on master as well):\n\n BUG: KASAN: slab-out-of-bounds in memcmp+0x98/0xd0\n Call trace:\n kasan_check_range+0xe8/0x190\n __asan_loadN+0x1c/0x28\n memcmp+0x98/0xd0\n efivarfs_d_compare+0x68/0xd8\n __d_lookup_rcu_op_compare+0x178/0x218\n __d_lookup_rcu+0x1f8/0x228\n d_alloc_parallel+0x150/0x648\n lookup_open.isra.0+0x5f0/0x8d0\n open_last_lookups+0x264/0x828\n path_openat+0x130/0x3f8\n do_filp_open+0x114/0x248\n do_sys_openat2+0x340/0x3c0\n __arm64_sys_openat+0x120/0x1a0\n\nIf dentry->d_name.len < EFI_VARIABLE_GUID_LEN , 'guid' can become\nnegative, leadings to oob. The issue can be triggered by parallel\nlookups using invalid filename:\n\n T1\t\t\tT2\n lookup_open\n ->lookup\n simple_lookup\n d_add\n // invalid dentry is added to hash list\n\n\t\t\tlookup_open\n\t\t\t d_alloc_parallel\n\t\t\t __d_lookup_rcu\n\t\t\t __d_lookup_rcu_op_compare\n\t\t\t hlist_bl_for_each_entry_rcu\n\t\t\t // invalid dentry can be retrieved\n\t\t\t ->d_compare\n\t\t\t efivarfs_d_compare\n\t\t\t // oob\n\nFix it by checking 'guid' before cmp."
},
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"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nefivarfs: Corrección de slab-out-of-bounds en efivarfs_d_compare\n\nObservado en el kernel 6.6 (presente también en master):\n\n BUG: KASAN: slab-out-of-bounds en memcmp+0x98/0xd0\n Traza de llamada:\n kasan_check_range+0xe8/0x190\n __asan_loadN+0x1c/0x28\n memcmp+0x98/0xd0\n efivarfs_d_compare+0x68/0xd8\n __d_lookup_rcu_op_compare+0x178/0x218\n __d_lookup_rcu+0x1f8/0x228\n d_alloc_parallel+0x150/0x648\n lookup_open.isra.0+0x5f0/0x8d0\n open_last_lookups+0x264/0x828\n path_openat+0x130/0x3f8\n do_filp_open+0x114/0x248\n do_sys_openat2+0x340/0x3c0\n __arm64_sys_openat+0x120/0x1a0\n\nSi dentry->d_name.len < EFI_VARIABLE_GUID_LEN, 'guid' puede volverse negativo, lo que lleva a oob. El problema puede ser provocado por búsquedas paralelas usando un nombre de archivo inválido:\n\n T1\t\t\tT2\n lookup_open\n ->lookup\n simple_lookup\n d_add\n // dentry inválido se añade a la lista hash\n\n\t\t\tlookup_open\n\t\t\t d_alloc_parallel\n\t\t\t __d_lookup_rcu\n\t\t\t __d_lookup_rcu_op_compare\n\t\t\t hlist_bl_for_each_entry_rcu\n\t\t\t // dentry inválido puede ser recuperado\n\t\t\t ->d_compare\n\t\t\t efivarfs_d_compare\n\t\t\t // oob\n\nCorríjalo verificando 'guid' antes de cmp."
}
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