---
id: CVE-2026-98127
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb/client: validate new EOF for insert range

  smb3_insert_range() does not check if the new file size
  (i_size + len) is valid
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb/client: validate new EOF for insert range

  smb3_insert_range() does not check if the new file size
  (i_size + len) is valid. This allows FALLOC_FL_INSERT_RANGE to by…
severity: medium
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 7fe6fe95b936084dce6eedcc2cccadf96eafae73 <
    7c2c69045aa76ccaa7f16f1478eb312130ce4951
  - >-
    Linux >= 7fe6fe95b936084dce6eedcc2cccadf96eafae73 <
    bc7602b9082ef195d913c4c16fa9853dd262333e
  - >-
    Linux >= 7fe6fe95b936084dce6eedcc2cccadf96eafae73 <
    f8cbfe3a3fcee7d991fd223f660f3e5df13221cf
  - >-
    Linux >= 7fe6fe95b936084dce6eedcc2cccadf96eafae73 <
    1519dc88c87f5346dae0464d7d6da1b6bf1f6e8e
  - Linux 5.13
published: '2026-09-25'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T14:10:59.253'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98127'
references:
  - url: 'https://git.kernel.org/stable/c/1519dc88c87f5346dae0464d7d6da1b6bf1f6e8e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7c2c69045aa76ccaa7f16f1478eb312130ce4951'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bc7602b9082ef195d913c4c16fa9853dd262333e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f8cbfe3a3fcee7d991fd223f660f3e5df13221cf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98127.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98127'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541317'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98127'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98127'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98127.mbox
  - url: 'https://git.kernel.org/stable/c/b7f2e33d9f5db7b8e6e5e0a5a93d0c5e31870356'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.0013
epssPercentile: 0.02626
ingestedAt: '2026-09-25T11:06:38.818Z'
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe:
  - CWE-1284
---

## Overview

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

smb/client: validate new EOF for insert range

smb3_insert_range() does not check if the new file size
(i_size + len) is valid. This allows FALLOC_FL_INSERT_RANGE to bypass
RLIMIT_FSIZE, exceed s_maxbytes, or produce a size outside the loff_t
range.

Use check_add_overflow() to calculate the new EOF. Validate it with
inode_newsize_ok() before modifying the file.

Reproducer, using a file on a CIFS mount:

	bash -c '
		FILE=/mnt/cifs/repro

		trap "" SIGXFSZ
		ulimit -f 3072		# RLIMIT_FSIZE = 3 MiB

		# A regular write is stopped at 3 MiB.
		dd if=/dev/zero of="$FILE" bs=1M count=4 status=none
		stat -c "size after write: %s" "$FILE"

		# Insert 2 MiB into a 2 MiB file.
		truncate -s 2M "$FILE"
		fallocate -i -o 0 -l 2M "$FILE"
		stat -c "size after insert: %s" "$FILE"
	'

Before this change, the regular write stops at the 3 MiB limit, but
insert range grows the file to 4 MiB:

	dd: error writing '/mnt/cifs/repro': File too large
	size after write: 3145728
	size after insert: 4194304

After this change, insert range also fails at the limit and leaves the
2 MiB file unchanged:

	dd: error writing '/mnt/cifs/repro': File too large
	size after write: 3145728
	fallocate: fallocate failed: File too large
	size after insert: 2097152

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98127.json)