---
id: CVE-2026-99137
title: 'cifs: don''t update i_size in cifs_do_truncate without a cached handle'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: don't update i_size in cifs_do_truncate without a cached handle

  If find_writable_file() returns null, cifs_file_flush will return
  0 without issuing set_file_size…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 110fee6b9bb58a5c50047fc2594d415f741b591e <
    04d020b3d0b58a1b7e116900e4095b96a7f4e11a
  - >-
    Linux >= 110fee6b9bb58a5c50047fc2594d415f741b591e <
    88a51743cd8094b76fd910f53f718747c7729cc8
  - >-
    Linux >= 110fee6b9bb58a5c50047fc2594d415f741b591e <
    fe39cd9d48f2346605f3746e0cc19e89d5f373eb
  - Linux 6.18
published: '2026-10-28'
updated: '2026-10-28'
sourceUpdated: '2026-10-28T10:34:49.266Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99137'
references:
  - url: 'https://git.kernel.org/stable/c/04d020b3d0b58a1b7e116900e4095b96a7f4e11a'
  - url: 'https://git.kernel.org/stable/c/88a51743cd8094b76fd910f53f718747c7729cc8'
  - url: 'https://git.kernel.org/stable/c/fe39cd9d48f2346605f3746e0cc19e89d5f373eb'
tags:
  - cve.org
ingestedAt: '2026-10-28T11:09:40.433Z'
---

## Overview

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

cifs: don't update i_size in cifs_do_truncate without a cached handle

If find_writable_file() returns null, cifs_file_flush will return
0 without issuing set_file_size, and the outer 'if (!rc)' block
will set i_size to 0 before telling the server to truncate.  If
the cifs_open() then fails, the inode will have size 0, while
the server file is unchanged.

Move the netfs_resize_file() and cifs_setsize() into the 'if
(cfile)', so they only run after a successful set_file_size.

In the no-handle else branch, evict stale pages with
truncate_inode_pages before the O_TRUNC open to dispose of old
cache pages, and let the open response set the i_size.

## Affected

- `Linux >= 110fee6b9bb58a5c50047fc2594d415f741b591e < 04d020b3d0b58a1b7e116900e4095b96a7f4e11a`
- `Linux >= 110fee6b9bb58a5c50047fc2594d415f741b591e < 88a51743cd8094b76fd910f53f718747c7729cc8`
- `Linux >= 110fee6b9bb58a5c50047fc2594d415f741b591e < fe39cd9d48f2346605f3746e0cc19e89d5f373eb`
- `Linux 6.18`

## Remediation

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