---
id: "CVE-2026-99114"
kind: "vulnerability"
aliases: ["CVE-2026-99114"]
title: "Linux kernel ksmbd: uninitialized memory returned in SMB filesystem control info"
severity: "low"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["file-server", "ksmbd", "linux-kernel", "runtime", "self-hosted"]
not_affected_if: ["ksmbd-not-enabled", "samba-userspace"]
published_at: "2026-10-28T11:17:30+00:00"
first_seen_at: "2026-10-28T11:32:34+00:00"
updated_at: "2026-10-28T11:37:40+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99114", "first_seen_at": "2026-10-28T11:32:34+00:00"}]
---

# Linux kernel ksmbd: uninitialized memory returned in SMB filesystem control info

In the ksmbd SMB server in the Linux kernel, the FS_CONTROL_INFORMATION reply never sets FileSystemControlFlags, so four bytes of leftover response-buffer memory are sent to the client. In a compound request, stale data from a dropped earlier reply can be carried into the next response.

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

## Timeline

- 2026-10-28T11:32:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-99114

## From the sources

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

ksmbd: initialize FileSystemControlFlags in FS_CONTROL_INFORMATION

smb2_get_info_filesystem() reports 48 bytes for FS_CONTROL_INFORMATION,
that is the whole of struct smb2_fs_control_info, but never assigns
FileSystemControlFlags.  Those four bytes go to the client as they are
found in the response buffer.

The buffer is zeroed on allocation, so a standalone request leaks
nothing.  A compound request can leak: the offset of the next response
is advanced by the length pinned for the previous one, so a reply that
was written into the buffer and then dropped in favour of the short
error response of smb2_set_err_rsp() stays there, and the next reply is
laid over it with only the header cleared.

ksmbd does not implement quota tracking, so report no control flags.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_