Linux Kernel RDMA/siw siw_accept Connection Establishment Race Frees QP and cep Under Lock, Enabling a Local Use-After-Free

Status: UPDATED  |  Advisory ID: CVE-2026-98367

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

RDMA/siw: Clear association under lock if siw_qp_modify fails in siw_accept

We need to clear cep before release state_lock as siw_qp_llp_close and

siw_qp_modify->siw_qp_llp_close did.

Otherwise if siw_qp_modify() fails in siw_accept(), the QP's state_lock

is released before the error path cleanup. A concurrent ibv_modify_qp()

transitioning the QP to ERROR can race in this window:

siw_accept() ibv_modify_qp(ERROR)

---------------------- ----------------------

siw_qp_modify() fails

up_write(&qp->state_lock)

down_write(&qp->state_lock)

nextstate_from_idle():

if (qp->cep)

siw_cep_put(qp->cep) <- frees cep

qp->cep = NULL

goto error

cep->qp = NULL <- UAF

Clear qp->cep and drop the association reference taken by siw_cep_get(),

all under the write lock held from the initial down_write(&qp->state_lock).

Thread B therefore sees qp->cep == NULL, skips its own put, and cannot free

the cep before siw_accept() is done with it. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References