Race condition in Linux kernel - CVE-2026-43121
Published: May 7, 2026
Vulnerability identifier: #VU130626
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-43121
CWE-ID: CWE-362
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a race condition leading to double free and out-of-bounds write in io_uring zcrx niov freelist handling when concurrent scrub and refill paths manipulate user_refs. A local user can trigger concurrent operations to cause a denial of service.
The issue occurs on SMP systems due to unsynchronized access to the same reference counter.
How to mitigate CVE-2026-43121
Install security update from vendor's repository.