CVE-2025-37838

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

HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition

In the ssi_protocol_probe() function, &ssi->work is bound with ssip_xmit_work(), In ssip_pn_setup(), the ssip_pn_xmit() function within the ssip_pn_ops structure is capable of starting the work.

If we remove the module which will call ssi_protocol_remove() to make a cleanup, it will free ssi through kfree(ssi), while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows:

CPU0 CPU1

                    | ssip_xmit_work

ssi_protocol_remove | kfree(ssi); | | struct hsi_client *cl = ssi->cl; | // use ssi

Fix it by ensuring that the work is canceled before proceeding with the cleanup in ssi_protocol_remove().

This vulnerability does not affect Red Hat Enterprise Linux as the High-Speed Synchronous Serial Interface (HSI) ssi_protocol driver is not enabled or shipped in Red Hat enterprise kernels. Upstream, the flaw involves a race condition leading to a use-after-free condition during driver removal, which would require local administrative privileges to unload the module. Because the underlying code is not present in supported Red Hat products, this issue poses no risk to Red Hat environments.