---
id: CVE-2025-40268
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: client: fix memory leak in smb3_fs_context_parse_param

  The user calls fsconfig twice, but when the program exits, free() only
  frees ctx->source for the second fs…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: client: fix memory leak in smb3_fs_context_parse_param

  The user calls fsconfig twice, but when the program exits, free() only
  frees ctx->source for the second fs…
severity: none
published: '2025-12-06'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T20:10:00.197'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-40268'
references:
  - url: 'https://git.kernel.org/stable/c/4515743cc7a42e1d67468402a6420c195532a6fa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/48c17341577e25a22feb13d694374b61d974edbc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/868fc62811d3fabcf5685e14f36377a855d5412d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e8c73eb7db0a498cd4b22d2819e6ab1a6f506bd6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/299bc05e1475a4aa1eb985ade8f39e68c1bba9b9'
tags:
  - nvd
  - cve.org
epss: 0.00187
epssPercentile: 0.08259
ingestedAt: '2026-10-27T18:12:09.301Z'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= af1a3d2ba9543e99d78914d8fb88b61d0531d9a1 <
    299bc05e1475a4aa1eb985ade8f39e68c1bba9b9
  - >-
    Linux >= af1a3d2ba9543e99d78914d8fb88b61d0531d9a1 <
    868fc62811d3fabcf5685e14f36377a855d5412d
  - >-
    Linux >= af1a3d2ba9543e99d78914d8fb88b61d0531d9a1 <
    48c17341577e25a22feb13d694374b61d974edbc
  - >-
    Linux >= af1a3d2ba9543e99d78914d8fb88b61d0531d9a1 <
    4515743cc7a42e1d67468402a6420c195532a6fa
  - >-
    Linux >= af1a3d2ba9543e99d78914d8fb88b61d0531d9a1 <
    e8c73eb7db0a498cd4b22d2819e6ab1a6f506bd6
  - Linux 5.11
---

## Overview

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

cifs: client: fix memory leak in smb3_fs_context_parse_param

The user calls fsconfig twice, but when the program exits, free() only
frees ctx->source for the second fsconfig, not the first.
Regarding fc->source, there is no code in the fs context related to its
memory reclamation.

To fix this memory leak, release the source memory corresponding to ctx
or fc before each parsing.

syzbot reported:
BUG: memory leak
unreferenced object 0xffff888128afa360 (size 96):
  backtrace (crc 79c9c7ba):
    kstrdup+0x3c/0x80 mm/util.c:84
    smb3_fs_context_parse_param+0x229b/0x36c0 fs/smb/client/fs_context.c:1444

BUG: memory leak
unreferenced object 0xffff888112c7d900 (size 96):
  backtrace (crc 79c9c7ba):
    smb3_fs_context_fullpath+0x70/0x1b0 fs/smb/client/fs_context.c:629
    smb3_fs_context_parse_param+0x2266/0x36c0 fs/smb/client/fs_context.c:1438

## Remediation

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