Improper Validation in Linux Kernel by Vendor Leading to F2FS ACL Issues

CVE-2026-63814

What is CVE-2026-63814?

An improper validation vulnerability exists in the Linux kernel's F2FS file system, specifically concerning Access Control Lists (ACLs). The affected function, f2fs_acl_from_disk(), fails to properly validate ACL entry sizes, allowing a malformed ACL to potentially cause out-of-bounds read operations. This can occur when either ACL_USER or ACL_GROUP entries are placed in slots intended for shorter ACL entries. As a result, this defect can lead to significant security risks by mishandling privileges and permissions. Mitigations have been introduced to enforce stricter validation checks on entry sizes, ensuring that full entries are verified before accessing critical fields. This vulnerability underlines the importance of robust input validation in security-sensitive applications.

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