Off-by-one in Linux kernel - CVE-2026-46066
Published: May 28, 2026
Vulnerability identifier: #VU132423
CSH Severity: Low
CVSS v4: 5.7 [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]
CVE-ID: CVE-2026-46066
CWE-ID: CWE-193
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-raspi (Ubuntu package)
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-raspi (Ubuntu package)
How to mitigate CVE-2026-46066
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - update to 7.0.0-27.27
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-nvidia (Ubuntu package) - update to 7.0.0-1013.13
linux-raspi (Ubuntu package) - update to 7.0.0-1014.14
linux (Ubuntu package) - update to 7.0.0-27.27
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-nvidia (Ubuntu package) - update to 7.0.0-1013.13
linux-raspi (Ubuntu package) - update to 7.0.0-1014.14