Double free in Linux kernel - CVE-2026-43120
Published: May 7, 2026
Vulnerability identifier: #VU130647
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-2026-43120
CWE-ID: CWE-415
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 double free in rereg_user_mr when re-registering a memory region with IB_MR_REREG_TRANS set. A local user can trigger an error after a new umem is allocated and then call ibv_dereg_mr to cause a denial of service.
The issue occurs because a released umem reference remains non-NULL and is released again on the deregistration path.
How to mitigate CVE-2026-43120
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/0c5d70bcb9d2275a1c8515a924016fcfeb4ab441
- https://git.kernel.org/stable/c/0f22c32141acdcda266b26cab2b830baf870f3e0
- https://git.kernel.org/stable/c/29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2
- https://git.kernel.org/stable/c/62298a48f8b8788ad8b8464e6ffdf1ddebd2217e
- https://git.kernel.org/stable/c/66964118f1f50ed85001c8fc9f7ab5bbdd021ee0