CVE-2026-43076 ocfs2: validate inline data i_size during inode read
A use-after-free vulnerability in the Linux kernel's OCFS2 filesystem allows attackers to execute code or cause a denial of service via a corrupted filesystem image.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-43076?
CVE-2026-43076 is a high-severity use after free vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: validate inline data i_size during inode read
When reading an inode from disk, ocfs2_validate_inode_block() performs various sanity checks but does not validate the size of inline data. If the filesystem is corrupted, an inode's i_size can exceed the actual inline data capacity (id_count).
This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data buffer, triggering a use-after-free when accessing directory entries from freed memory.
In the syzbot report: - i_size was 1099511627576 bytes (~1TB) - Actual inline data capacity (id_count) is typically <256 bytes - A garbage rec_len (54648) caused ctx->pos to jump out of bounds - This triggered a UAF in ocfs2_check_dir_entry()
Fix by adding a validation check in ocfs2_validate_inode_block() to ensure inodes with inline data have i_size <= id_count. This catches the corruption early during inode read and prevents all downstream code from operating on invalid data.
Weakness: CWE-416
Which versions are affected by CVE-2026-43076?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43076?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-43076 being exploited?
There is no known exploitation of CVE-2026-43076 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43076, DEBIAN-CVE-2026-43076, GHSA-w594-5gj3-f9g6, ROOT-OS-DEBIAN-11-CVE-2026-43076, ROOT-OS-DEBIAN-12-CVE-2026-43076, ROOT-OS-UBUNTU-2204-CVE-2026-43076 and 2 more.