Linux Kernel ocfs2 fs/ocfs2/inode.c ocfs2_fast_symlink_read_folio use after free

Summaryinfo

A vulnerability classified as very critical was found in Linux Kernel. This issue affects the function ocfs2_fast_symlink_read_folio of the file fs/ocfs2/inode.c of the component ocfs2. The manipulation results in use after free. This vulnerability is identified as CVE-2026-74350. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel (version unknown). Affected is the function ocfs2_fast_symlink_read_folio of the file fs/ocfs2/inode.c of the component ocfs2. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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 (?:?)

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-74350 since 08/15/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/15/2026).

Applying the patch f9e2cb692b77a679b1f4cc2b7b277fa908586533/e234973f286ed2e8961a24561ec91594ec3e3ff8 is able to eliminate this problem.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

License

• open-source

Website

• Vendor: https://www.kernel.org/

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