AZL-111209: CVE-2026-99114 affecting package kernel 6.6.157.1-1

Q: Are standalone SMB requests affected?

No. A standalone FS_CONTROL_INFORMATION request does not leak data because the response buffer is zeroed when allocated. The leak requires a compound SMB request.

Q: What must an attacker do to trigger the disclosure?

The attacker must interact with ksmbd and send a compound request that causes a previously written response to be discarded in favor of a short error response, followed by an FS_CONTROL_INFORMATION response. The later response can expose the four-byte FileSystemControlFlags field from residual buffer contents.

Published Oct 28, 2026

Updated

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

ksmbd: initialize FileSystemControlFlags in FSCONTROLINFORMATION

smb2getinfofilesystem() reports 48 bytes for FSCONTROLINFORMATION, that is the whole of struct smb2fscontrolinfo, 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 smb2seterrrsp() 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.

Affected Software

1 affected component

azure-linux/kernel<=6.6.157.1-1

Event History

Oct 28, 2026

Advisory Published

via OSV·11:17 AM

Data Sourced

via OSV·11:17 AM

DescriptionAffected Software

Child vulnerabilities

Contains the following vulnerabilities.

CVE-2026-99114

Frequently Asked Questions

Are standalone SMB requests affected?

No. A standalone FS_CONTROL_INFORMATION request does not leak data because the response buffer is zeroed when allocated. The leak requires a compound SMB request.

What must an attacker do to trigger the disclosure?

The attacker must interact with ksmbd and send a compound request that causes a previously written response to be discarded in favor of a short error response, followed by an FS_CONTROL_INFORMATION response. The later response can expose the four-byte FileSystemControlFlags field from residual buffer contents.

AZL-111209: CVE-2026-99114 affecting package kernel 6.6.157.1-1

Affected Software

Event History

Child vulnerabilities

Frequently Asked Questions

Are standalone SMB requests affected?

What must an attacker do to trigger the disclosure?

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Frequently Asked Questions

Are standalone SMB requests affected?

What must an attacker do to trigger the disclosure?