Описание
In the Linux kernel, the following vulnerability has been resolved: ext4: fix use-after-free in ext4_orphan_cleanup I caught a issue as follows:
BUG: KASAN: use-after-free in __list_add_valid+0x28/0x1a0 Read of size 8 at addr ffff88814b13f378 by task mount/710 CPU: 1 PID: 710 Comm: mount Not tainted 6.1.0-rc3-next #370 Call Trace: dump_stack_lvl+0x73/0x9f print_report+0x25d/0x759 kasan_report+0xc0/0x120 __asan_load8+0x99/0x140 __list_add_valid+0x28/0x1a0 ext4_orphan_cleanup+0x564/0x9d0 [ext4] __ext4_fill_super+0x48e2/0x5300 [ext4] ext4_fill_super+0x19f/0x3a0 [ext4] get_tree_bdev+0x27b/0x450 ext4_get_tree+0x19/0x30 [ext4] vfs_get_tree+0x49/0x150 path_mount+0xaae/0x1350 do_mount+0xe2/0x110 __x64_sys_mount+0xf0/0x190 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...]
Above issue may happen as follows:
ext4_fill_super
ext4_orphan_cleanup
--- loop1: assume last_orphan is 12 ---
list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan)
ext4_truncate --> return 0
ext4_inode_attach_jinode --> return -ENOMEM
iput(inode) --> free inode<12>
--- loop2: last_orphan is still 12 ---
list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
// use inode<12> and trigger UAF
To solve this issue, we need to propagate the return value of
ext4_inode_attach_jinode() appropriately.
A use-after-free vulnerability was found in the ext4 filesystem's orphan inode cleanup routine in the Linux kernel. When ext4_inode_attach_jinode() fails with -ENOMEM during orphan cleanup at mount time, the error is not properly propagated. The inode is freed via iput(), but the orphan list still references the same inode number. On the next loop iteration, the freed inode structure is reused, triggering a use-after-free when adding it to the orphan list.
Отчет
This flaw occurs during ext4 filesystem mount when memory allocation fails at a specific point in orphan inode processing. Exploitation requires local access to mount ext4 filesystems and the ability to induce memory pressure during the mount operation, making practical exploitation difficult.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | kernel-rt | Fixed | RHSA-2026:3634 | 03.03.2026 |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | kernel | Fixed | RHSA-2026:3685 | 03.03.2026 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:2378 | 10.02.2026 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2026:2264 | 09.02.2026 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | kernel | Fixed | RHSA-2026:2664 | 12.02.2026 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | kernel | Fixed | RHSA-2026:3360 | 25.02.2026 |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | kernel | Fixed | RHSA-2026:3360 | 25.02.2026 |
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Дополнительная информация
Статус:
EPSS
7 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ext4: fix use-after-free in ext4_orphan_cleanup I caught a issue as follows: ================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x28/0x1a0 Read of size 8 at addr ffff88814b13f378 by task mount/710 CPU: 1 PID: 710 Comm: mount Not tainted 6.1.0-rc3-next #370 Call Trace: <TASK> dump_stack_lvl+0x73/0x9f print_report+0x25d/0x759 kasan_report+0xc0/0x120 __asan_load8+0x99/0x140 __list_add_valid+0x28/0x1a0 ext4_orphan_cleanup+0x564/0x9d0 [ext4] __ext4_fill_super+0x48e2/0x5300 [ext4] ext4_fill_super+0x19f/0x3a0 [ext4] get_tree_bdev+0x27b/0x450 ext4_get_tree+0x19/0x30 [ext4] vfs_get_tree+0x49/0x150 path_mount+0xaae/0x1350 do_mount+0xe2/0x110 __x64_sys_mount+0xf0/0x190 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> [...] ================================================================== Above issue may happen as follows: ------------------...
In the Linux kernel, the following vulnerability has been resolved: ext4: fix use-after-free in ext4_orphan_cleanup I caught a issue as follows: ================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x28/0x1a0 Read of size 8 at addr ffff88814b13f378 by task mount/710 CPU: 1 PID: 710 Comm: mount Not tainted 6.1.0-rc3-next #370 Call Trace: <TASK> dump_stack_lvl+0x73/0x9f print_report+0x25d/0x759 kasan_report+0xc0/0x120 __asan_load8+0x99/0x140 __list_add_valid+0x28/0x1a0 ext4_orphan_cleanup+0x564/0x9d0 [ext4] __ext4_fill_super+0x48e2/0x5300 [ext4] ext4_fill_super+0x19f/0x3a0 [ext4] get_tree_bdev+0x27b/0x450 ext4_get_tree+0x19/0x30 [ext4] vfs_get_tree+0x49/0x150 path_mount+0xaae/0x1350 do_mount+0xe2/0x110 __x64_sys_mount+0xf0/0x190 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> [...] ================================================================== Above issue
In the Linux kernel, the following vulnerability has been resolved: e ...
In the Linux kernel, the following vulnerability has been resolved: ext4: fix use-after-free in ext4_orphan_cleanup I caught a issue as follows: ================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x28/0x1a0 Read of size 8 at addr ffff88814b13f378 by task mount/710 CPU: 1 PID: 710 Comm: mount Not tainted 6.1.0-rc3-next #370 Call Trace: <TASK> dump_stack_lvl+0x73/0x9f print_report+0x25d/0x759 kasan_report+0xc0/0x120 __asan_load8+0x99/0x140 __list_add_valid+0x28/0x1a0 ext4_orphan_cleanup+0x564/0x9d0 [ext4] __ext4_fill_super+0x48e2/0x5300 [ext4] ext4_fill_super+0x19f/0x3a0 [ext4] get_tree_bdev+0x27b/0x450 ext4_get_tree+0x19/0x30 [ext4] vfs_get_tree+0x49/0x150 path_mount+0xaae/0x1350 do_mount+0xe2/0x110 __x64_sys_mount+0xf0/0x190 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> [...] ================================================================== Above is...
Уязвимость функции ext4_truncate() модуля fs/ext4/inode.c файловой системы Ext4 ядра операционной системы Linux, позволяющая нарушителю оказать воздействие на конфиденциальность, целостность и доступность защищаемой информации
EPSS
7 High
CVSS3