CVE-2026-43076: ocfs2: validate inline data i_size during inode read

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-06 · updated 2026-06-17
Weakness: CWE-416

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.

Affected products

Linux kernel: from 2.6.24.1 before 6.6.136; from 6.7 before 6.12.83; from 6.13 before 6.18.24; from 6.19 before 6.19.14; 2.6.24, 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5 (+2) — fixed in 6.12.83, 6.18.24, 6.19.14, 6.6.136

How to fix

Upgrade to a fixed version: Linux kernel 6.12.83, 6.18.24, 6.19.14, 6.6.136. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-43076 or the next vulnerability affects your stack