---
id: "CVE-2026-99280"
page: "https://infrastack.ai/live/CVE-2026-99280"
kind: "vulnerability"
aliases: ["CVE-2026-99280"]
title: "Linux kernel ksmbd: session procfs race can crash the SMB server"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["ksmbd", "linux", "runtime", "self-hosted", "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: "2026-11-07T14:49:49+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99280", "first_seen_at": "2026-11-07T14:47:40+00:00"}]
exploit_sources: []
---

# Linux kernel ksmbd: session procfs race can crash the SMB server

Link for people: https://infrastack.ai/live/CVE-2026-99280 (this .md is for agents)

A race in the Linux kernel's ksmbd SMB file server lets session cleanup remove procfs entries while a reader still uses them, which can corrupt memory. The sources do not state what an attacker can gain beyond a crash or instability.

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

## How to check

- Check whether the kernel has the ksmbd module loaded, for example with `lsmod | grep ksmbd`.
- Check the running kernel version with `uname -r` and compare it with the fixed kernel in the kernel.org stable branch the distribution ships.

## Timeline

- 2026-11-07T14:47:40+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-99280

## From the sources

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

ksmbd: drain session procfs readers before dropping table references

Session registration failure and connection cleanup can drop the table
reference while the per-session procfs entry is still accessible. If a
reader holds the last remaining reference, its final put calls
proc_remove() from its own callback and waits for that callback to
finish.

Remove the procfs entry before dropping the table reference in the
registration failure path. Queue sessions removed during connection
cleanup and drain their procfs readers after releasing both session
locks, then return their table references. Keep the global hash node
unhashed while a session is queued so a concurrent unregister cannot
drop the reference again.

Previous-session replacement also destroys the file table before the
session is finally freed. Detach the idr under the lock used by procfs
file counters, and report zero files after it has been detached. This
prevents a reader from accessing the idr during or after its
destruction.

---

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