SB2026052803 - Off-by-one in Linux kernel ceph

Description

This security bulletin contains information about 1 vulnerability.

1) Off-by-one (CVE-ID: CVE-2026-46066)

CWE-ID: CWE-193 - Off-by-one Error

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to an off-by-one error in ceph_process_folio_batch() when handling encrypted CephFS writeback after bounce buffer allocation failure. A local user can write to fscrypt-enabled CephFS files under memory pressure to trigger a kernel panic and cause a denial of service.

The issue is triggered when processing a 4KiB-written/4KiB-skipped pattern and the failed folio is not contiguous with the last folio already added to the batch.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/6200f41d6fcf2ac7e24866431e381cbc914560e4
• https://git.kernel.org/stable/c/a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842
• https://git.kernel.org/stable/c/ba12c1e578890f6337a415b7dedf476c6d455105