---
id: "CVE-2026-99277"
page: "https://infrastack.ai/live/CVE-2026-99277"
kind: "vulnerability"
aliases: ["CVE-2026-99277"]
title: "Linux kernel: ksmbd session cleanup can free a connection still in use"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["file-server", "kernel", "ksmbd", "linux", "runtime", "smb"]
not_affected_if: ["ksmbd-not-loaded", "samba-only"]
published_at: "2026-11-07T14:17:03+00:00"
first_seen_at: "2026-11-07T14:47:40+00:00"
updated_at: "2026-11-07T14:49:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99277", "first_seen_at": "2026-11-07T14:47:40+00:00"}]
exploit_sources: []
---

# Linux kernel: ksmbd session cleanup can free a connection still in use

Link for people: https://infrastack.ai/live/CVE-2026-99277 (this .md is for agents)

A race in the Linux kernel's ksmbd SMB server lets a connection be freed while another session reference still uses it. The sources do not state what an attacker gets beyond a crash or memory misuse in the kernel.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check whether the kernel was built with ksmbd: `grep -i ksmbd /boot/config-$(uname -r)` (CONFIG_SMB_SERVER set)
- Check whether the ksmbd service is running: `lsmod | grep ksmbd`

## Timeline

- 2026-11-07T14:47:40+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-99277

## From the sources

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

ksmbd: hold a connection reference for each session channel

ksmbd_session_unregister() removes a session from the global and per-
connection tables before dropping the table reference. A concurrent
reference holder can keep the session and its channel list alive after
those removals.

Connection cleanup can no longer find the unpublished session to remove its
channels. Since a channel only stores a raw conn pointer, the connection
can be freed while another session reference holder is still accessing it,
for example during SMB3.1.1 binding or a procfs read.

Take a connection reference when registering a channel and release it on
insertion failure, channel removal, or final session destruction. Keep the
channels and signing keys until the session is destroyed so a response can
still be signed after the session has been unregistered.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_