In the Linux kernel, the following vulnerability has been resolved:
RDMA/siw: Fix endpoint/socket association handling
Disassociating a socket from an endpoint via siw_socket_disassoc() may
release the last reference on that endpoint and free it. Therefore, don't
clear the endpoints socket pointer after calling that function, but
within.
This fixes a:
BUG: KASAN: slab-use-after-free in siw_cm_work_handler (drivers/infiniband/sw/siw/siw_cm.c:1053 drivers/infiniband/sw/siw/siw_cm.c:1075)
which occurred after processing a malformed MPA request during connection
establishment, causing the new endpoint to be closed.
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 9.8
AV:N - The bug is hit while processing attacker-supplied MPA/TCP data on an inbound SIW listener socket during connection establishment, which is a standard network protocol path analogous to other in-kernel TCP service handlers.
AC:L - An attacker fully controls the TCP connection and malformed MPA request bytes that deterministically fail parsing and drive the endpoint teardown path where the refcount bug frees the cep before it is accessed again.
PR:N - Exploitation requires only the ability to open a TCP connection to a host running an SIW RDMA listener; the MPA handshake is unauthenticated and occurs before any RDMA credentials or local privileges are established.
UI:N - No end-user action is required at exploit time; the kernel processes the malicious inbound connection automatically once an administrator has started an RDMA listener service.
S:U - Impact is confined to kernel memory corruption and potential host privilege escalation within the same kernel security authority, not a VM escape or cross-authority boundary such as guest-to-hypervisor.
C:H - The vulnerability is a slab use-after-free on a freed siw_cep object; UAF on attacker-influenced connection teardown enables heap grooming and arbitrary kernel memory read primitives beyond a simple crash.
I:H - Use-after-free of the connection endpoint structure in kernel heap can be leveraged for controlled writes and code execution via object reuse and function pointer/callback corruption, not merely data integrity of a single field.
A:H - The bug was reproduced as a KASAN slab-use-after-free in siw_cm_work_handler during malformed MPA processing, which can cause kernel oops/panic and denial of service on the target host.
| Attack Vector |
Network |
Scope |
Unchanged |
| Attack Complexity |
Low |
Confidentiality Impact |
High |
| Privileges Required |
None |
Integrity Impact |
High |
| User Interaction |
None |
Availability Impact |
High |
AV:N - The bug is hit while processing attacker-supplied MPA/TCP data on an inbound SIW listener socket during connection establishment, which is a standard network protocol path analogous to other in-kernel TCP service handlers.
AC:L - An attacker fully controls the TCP connection and malformed MPA request bytes that deterministically fail parsing and drive the endpoint teardown path where the refcount bug frees the cep before it is accessed again.
PR:N - Exploitation requires only the ability to open a TCP connection to a host running an SIW RDMA listener; the MPA handshake is unauthenticated and occurs before any RDMA credentials or local privileges are established.
UI:N - No end-user action is required at exploit time; the kernel processes the malicious inbound connection automatically once an administrator has started an RDMA listener service.
S:U - Impact is confined to kernel memory corruption and potential host privilege escalation within the same kernel security authority, not a VM escape or cross-authority boundary such as guest-to-hypervisor.
C:H - The vulnerability is a slab use-after-free on a freed siw_cep object; UAF on attacker-influenced connection teardown enables heap grooming and arbitrary kernel memory read primitives beyond a simple crash.
I:H - Use-after-free of the connection endpoint structure in kernel heap can be leveraged for controlled writes and code execution via object reuse and function pointer/callback corruption, not merely data integrity of a single field.
A:H - The bug was reproduced as a KASAN slab-use-after-free in siw_cm_work_handler during malformed MPA processing, which can cause kernel oops/panic and denial of service on the target host.
CVSS 3.1