---
id: CVE-2025-9640
title: >-
  A flaw was found in Samba, in the vfs_streams_xattr module, where
  uninitialized heap memory could be written into alternate data streams
summary: >-
  A flaw was found in Samba, in the vfs_streams_xattr module, where
  uninitialized heap memory could be written into alternate data streams. This
  allows an authenticated user to read residual memory content that may include
  sensitive data, …
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-908
  - CWE-908
published: '2025-10-15'
updated: '2026-06-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-9640'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2025-9640'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2391698'
    label: secalert@redhat.com
  - url: 'https://www.samba.org/samba/history/security.html'
    label: secalert@redhat.com
  - url: 'http://www.openwall.com/lists/oss-security/2025/10/15/2'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://www.openwall.com/lists/oss-security/2025/10/16/2'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/11/msg00027.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00462
epssPercentile: 0.39323
ingestedAt: '2026-06-29T13:24:34.588Z'
---

## Overview

A flaw was found in Samba, in the vfs_streams_xattr module, where uninitialized heap memory could be written into alternate data streams. This allows an authenticated user to read residual memory content that may include sensitive data, resulting in an information disclosure vulnerability.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.