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CVE-2026-92499: Linux

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CVSS

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Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

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    Оригинално описание

    In the Linux kernel, the following vulnerability has been resolved: ext4: validate readdir offset before accessing dirent A corrupted directory can trigger the following KASAN report when ext4_readdir() resumes from an invalid position: BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x5ef/0x820 Read of size 2 at addr ffff88810a646000 by task repro_linear/509 Call Trace: <TASK> dump_stack_lvl+0x53/0x70 print_report+0xd0/0x630 kasan_report+0xce/0x100 __ext4_check_dir_entry+0x5ef/0x820 ext4_readdir+0xcde/0x2b70 iterate_dir+0x1a1/0x520 __x64_sys_getdents64+0x12b/0x220 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> KASAN reports use-after-free because the out-of-bounds access lands in an adjacent freed page. The directory buffer itself is still referenced. ext4_dir_llseek() invalidates the directory cookie so that ext4_readdir() rescans directory entries from the start of the block. The rescan checks only the lower bound of rec_len before advancing. A corrupted rec_len can therefore place the offset where the block has insufficient space for a complete directory entry. The rescan itself may dereference that truncated entry, or the main loop may pass it to __ext4_check_dir_entry(). The latter reads de->rec_len before validating the range. For example: block offset 0 4092 4096 |---- de1.rec_len = 4092 -----|----| de2.inode | de2.rec_len ^ OOB, reported as UAF de2 starts at offset 4092 in this 4 KiB block. Its four-byte inode fits in the block, but its rec_len starts at offset 4096 and crosses the boundary. The minimum safe length is inode-dependent. Encrypted and casefolded directory entries need eight additional hash bytes, while a valid metadata checksum tail is only 12 bytes. Cache the metadata c

    Засегнати продукти

    • Linux Linux: ac27a0ec112a089f1a5102bc8dffc79c8c815571 преди 64d445d40e5ea4c4d4d88880db753b370cb69161; ac27a0ec112a089f1a5102bc8dffc79c8c815571 преди b4c728577933753180e3e97f08424d5bcaff705e; ac27a0ec112a089f1a5102bc8dffc79c8c815571 преди bc4b7b0414c33b2c8898eb04386df0d21a13dad8
    • Linux Linux: 2.6.19; преди 2.6.19; 6.18.52 до 6.18.*; 7.2.6 до 7.2.*; от 7.3 нататък

    История

    • 17 септември 2026 Публикувано

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