---
id: CVE-2026-31675
title: 'net/sched: sch_netem: fix out-of-bounds access in packet corruption'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: sch_netem: fix out-of-bounds access in packet corruption

  In netem_enqueue(), the packet corruption logic uses
  get_random_u32_below(skb_headlen(skb)) to sele…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 <
    a14b56863348686dd0387eea8ce66b85cf455908
  - >-
    Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 <
    13a66ca1e235d4bcd53d12d4c68490cad7f8e46f
  - >-
    Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 <
    3a2999704ac36cfb4041fed3652d26a3373e8d12
  - >-
    Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 <
    4fd258e281fa8bc15e9ce2c7691941537e9258ad
  - >-
    Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 <
    d64cb81dcbd54927515a7f65e5e24affdc73c14b
  - Linux 2.6.16
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:12:12.570875Z'
published: '2026-04-25'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:23.263Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-31675'
references:
  - url: 'https://git.kernel.org/stable/c/a14b56863348686dd0387eea8ce66b85cf455908'
  - url: 'https://git.kernel.org/stable/c/13a66ca1e235d4bcd53d12d4c68490cad7f8e46f'
  - url: 'https://git.kernel.org/stable/c/3a2999704ac36cfb4041fed3652d26a3373e8d12'
  - url: 'https://git.kernel.org/stable/c/4fd258e281fa8bc15e9ce2c7691941537e9258ad'
  - url: 'https://git.kernel.org/stable/c/d64cb81dcbd54927515a7f65e5e24affdc73c14b'
tags:
  - cve.org
epss: 0.00184
epssPercentile: 0.07435
ingestedAt: '2026-10-16T17:24:46.670Z'
---

## Overview

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

net/sched: sch_netem: fix out-of-bounds access in packet corruption

In netem_enqueue(), the packet corruption logic uses
get_random_u32_below(skb_headlen(skb)) to select an index for
modifying skb->data. When an AF_PACKET TX_RING sends fully non-linear
packets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.

Passing 0 to get_random_u32_below() takes the variable-ceil slow path
which returns an unconstrained 32-bit random integer. Using this
unconstrained value as an offset into skb->data results in an
out-of-bounds memory access.

Fix this by verifying skb_headlen(skb) is non-zero before attempting
to corrupt the linear data area. Fully non-linear packets will silently
bypass the corruption logic.

## Affected

- `Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 < a14b56863348686dd0387eea8ce66b85cf455908`
- `Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 < 13a66ca1e235d4bcd53d12d4c68490cad7f8e46f`
- `Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 < 3a2999704ac36cfb4041fed3652d26a3373e8d12`
- `Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 < 4fd258e281fa8bc15e9ce2c7691941537e9258ad`
- `Linux >= c865e5d99e25a171e8262fc0f7ba608568633c64 < d64cb81dcbd54927515a7f65e5e24affdc73c14b`
- `Linux 2.6.16`

## Remediation

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