CVE-2026-90292: RDMA/siw: Fix use-after-free in siw_accept()

CVE-2026-90292: RDMA/siw: Fix use-after-free in siw_accept()

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

RDMA/siw: Fix use-after-free in siw_accept()

siw_accept() looks up the QP supplied by userspace. If that QP is
already in RTS, the function jumps to error cleanup before associating
the incoming CEP with it.

The cleanup tests whether qp->cep is non-NULL and assumes the current
call installed the association. However, qp->cep can point to the CEP
of an existing connection. The cleanup then drops a reference from the
incoming cep, not qp->cep. Once the incoming endpoint loses its
remaining references, this can free it before the subsequent cep->qp
store, causing a use-after-free. It also clears the existing QP
association.

Only release the association reference when qp->cep is the incoming
CEP. This preserves an existing association and avoids accessing the
freed endpoint.

The Linux kernel CVE team has assigned CVE-2026-90292 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 5.10.270 with commit d57db36e74cca4763e1c2c0c6eb9f84d19813879
	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 5.15.221 with commit 59de5502f32895ffe9c45530327ed997b90fdf06
	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 6.1.188 with commit a89d120615e711ce8fce551fd291c2f387666735
	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 6.6.157 with commit b9e7d3d9fdb2bfcfb25d93529fdf766536b37c78
	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 6.12.110 with commit 8f286a8094ee32c415f9ecd2c20765beb8a18c79
	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 6.18.52 with commit de603f01d9ccf823e575b013ffd86ebedca9a8c5
	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 7.2.6 with commit 561651d6a15588cee2040755f253faca2463415c
	Issue introduced in 5.3 with commit 6c52fdc244b5ccc468006fd65a504d4ee33743c7 and fixed in 7.3-rc1 with commit a9394971825933074032794a5feee5211509c774

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-90292
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/infiniband/sw/siw/siw_cm.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/d57db36e74cca4763e1c2c0c6eb9f84d19813879
	https://git.kernel.org/stable/c/59de5502f32895ffe9c45530327ed997b90fdf06
	https://git.kernel.org/stable/c/a89d120615e711ce8fce551fd291c2f387666735
	https://git.kernel.org/stable/c/b9e7d3d9fdb2bfcfb25d93529fdf766536b37c78
	https://git.kernel.org/stable/c/8f286a8094ee32c415f9ecd2c20765beb8a18c79
	https://git.kernel.org/stable/c/de603f01d9ccf823e575b013ffd86ebedca9a8c5
	https://git.kernel.org/stable/c/561651d6a15588cee2040755f253faca2463415c
	https://git.kernel.org/stable/c/a9394971825933074032794a5feee5211509c774