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Linux Kernel SMB Client Leaves Reconnect Delayed Work Running After Socket Close, Creating a Network-Triggered Use-After-Free

Last refreshed2026-10-10

Status: UPDATED  |  Advisory ID: CVE-2026-98175

Key Details

CVECVE-2026-98175
CVSS Score / Version7.5 (High) / CVSS v3.1
Updated2026-10-07
CVSS VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS Proseattack vector is network; attack complexity is high; privileges required is none; user interaction is required; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected productsLinux Kernel

Affected Products, Subsystems & Sectors

VendorProductAffected VersionsPatch Status
LinuxLinux Kernel
SubsystemsOT Supporting Infrastructure
SectorsAll Sectors

What to Know

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.

What to Do

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

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-98175
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-98175