CVE-2026-74350

CriticalCVSS 9.8

Published: 15/08/2026(UTC)Updated: 17/08/2026(UTC)Translated: 15/08/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.16%

5th percentile - higher than 5% of all known CVEs

Summary

In the Linux kernel, a vulnerability in the OCFS2 filesystem was found due to missing validation of fast symlinks during inode read. A corrupted inode with a zero-cluster symlink can cause an out-of-bounds read beyond the inode block buffer, leading to a use-after-free error.

Risk Assessment

An attacker with local access to an OCFS2 filesystem could exploit this vulnerability to cause a kernel crash or potentially escalate privileges, threatening system integrity and availability.

Recommendation

Apply the Linux kernel patch that adds validation of fast symlinks during inode read immediately. Avoid mounting untrusted OCFS2 filesystems until the update is applied.

Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate fast symlink target during inode read ocfs2_validate_inode_block() already rejects several inconsistent self-contained dinodes before they are exposed to the rest of the filesystem. Fast symlinks need the same treatment. A zero-cluster symlink is treated as a fast symlink and later read through page_get_link() and ocfs2_fast_symlink_read_folio(). That path uses strnlen() on the inline payload and then copies len + 1 bytes into the folio. If a corrupt dinode stores an i_size that does not fit the inline area or omits the terminating NUL at i_size, that copy reads past the end of the inode block buffer. Reject zero-cluster symlink dinodes whose i_size exceeds the inline fast-symlink capacity or whose inline payload is not NUL-terminated exactly at i_size when the inode block is validated. This keeps malformed fast symlinks from reaching the read path. Validation reproduced this kernel report: KASAN use-after-free in ocfs2_fast_symlink_read_folio+0x12c/0x1f0 RIP: 0033:0x7f5c6d859aa7 Read of size 3905 Call trace: dump_stack_lvl+0x66/0xa0 (?:?) print_report+0xce/0x630 (?:?) ocfs2_fast_symlink_read_folio+0x12c/0x1f0 (fs/ocfs2/inode.c:?) srso_alias_return_thunk+0x5/0xfbef5 (?:?) __virt_addr_valid+0x19f/0x330 (?:?) kasan_report+0xe0/0x110 (?:?) kasan_check_range+0x105/0x1b0 (?:?) __asan_memcpy+0x23/0x60 (?:?) filemap_read_folio+0x27/0xe0 (?:?) filemap_read_folio+0x35/0xe0 (?:?) do_read_cache_folio+0x138/0x230 (?:?) __page_get_link+0x26/0x110 (?:?) page_get_link+0x2e/0x70 (?:?) vfs_readlink+0x15e/0x250 (?:?) touch_atime+0x4d/0x370 (?:?) do_readlinkat+0x186/0x200 (?:?) do_user_addr_fault+0x65a/0x890 (?:?) __x64_sys_readlink+0x46/0x60 (?:?) do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)