CVE-2026-74350

Received Received - Intake

Buffer Overflow in OCFS2 Fast Symlink Handling

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

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 (?:?)

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-74350

EUVD

EUVD-2026-59497

Affected Vendors & Products

Vendor	Product	Version / Range
oracle	ocfs2	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves improper validation of fast symlinks in the OCFS2 filesystem. When reading an inode block, a corrupt directory entry (dinode) with a zero-cluster symlink could have an i_size value that exceeds the inline fast-symlink capacity or lacks a proper NUL terminator. This causes the kernel to read past the end of the inode block buffer during symlink operations, leading to a use-after-free memory error.

Detection Guidance

This vulnerability affects the OCFS2 filesystem in the Linux kernel. Detection primarily involves checking the kernel version and OCFS2 module for known vulnerable states. Use uname -a to check your kernel version and grep for OCFS2 in loaded modules with lsmod | grep ocfs2. If your kernel is older than the patched version, the system may be vulnerable.

Impact Analysis

This vulnerability could allow an attacker with local access to trigger a kernel memory corruption issue by exploiting a malformed symlink. This may result in system crashes, data corruption, or potential privilege escalation if the kernel's memory is compromised.

Compliance Impact

This vulnerability does not directly impact compliance with standards like GDPR or HIPAA. It is a Linux kernel issue affecting the ocfs2 filesystem, causing potential memory corruption via malformed symlinks. Compliance risks would only arise if this flaw enabled unauthorized data access or integrity breaches in systems handling regulated data.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for CVE-2026-74350. If immediate kernel update is not possible, disable the OCFS2 filesystem module by running rmmod ocfs2 and prevent it from loading at boot by blacklisting it in /etc/modprobe.d/. Ensure no critical services rely on OCFS2 during this period.

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