CVE-2026-98175

About vulnerability

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

smb: client: cancel reconnect work in clean_demultiplex_info()

clean_demultiplex_info() cancels server->echo delayed work but not server->reconnect, which can cause a use-after-free when the demultiplex thread exits while a reconnect work is still queued:

cifs_demultiplex_thread() cifs_readv_from_socket() cifs_reconnect() __cifs_reconnect() cifs_queue_server_reconn() mod_delayed_work(cifsiod_wq, &server->reconnect, 0) clean_demultiplex_info() cancel_delayed_work_sync(&server->echo) // echo canceled // reconnect NOT canceled kfree_sensitive(server) // server freed

…later, on cifsiod_wq:

smb2_reconnect_server() server->srv_count // UAF read of freed server

Fix this by canceling server->reconnect delayed work in clean_demultiplex_info() before the server is freed, the same way cifs_put_tcp_session() already does.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

linux @ 5.10.259 (+12 more)

Live-patch status from KernelCare for each operating system.