---
id: CVE-2025-38115
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net_sched: sch_sfq: fix a potential crash on gso_skb handling

  SFQ has an assumption of always being able to queue at least one packet.

  However, after the blamed commi…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net_sched: sch_sfq: fix a potential crash on gso_skb handling

  SFQ has an assumption of always being able to queue at least one packet.

  However, after the blamed commi…
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'
cwe:
  - CWE-401
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 4.16, < 5.4.295'
  - 'linux_kernel >= 5.5, < 5.10.239'
  - 'linux_kernel >= 5.11, < 5.15.186'
  - 'linux_kernel >= 5.16, < 6.1.142'
  - 'linux_kernel >= 6.2, < 6.6.94'
  - 'linux_kernel >= 6.7, < 6.12.34'
  - 'linux_kernel >= 6.13, < 6.15.3'
  - linux_kernel = 6.16
  - debian_linux = 11.0
patched:
  - linux_kernel 6.15.3
published: '2025-07-03'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:18:27.983'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-38115'
references:
  - url: 'https://git.kernel.org/stable/c/5814a7fc3abb41f63f2d44c9d3ff9d4e62965b72'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/82448d4dcd8406dec688632a405fdcf7f170ec69'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/82ffbe7776d0ac084031f114167712269bf3d832'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9c19498bdd7cb9d854bd3c54260f71cf7408495e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b44f791f27b14c9eb6b907fbe51f2ba8bec32085'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b4e9bab6011b9559b7c157b16b91ae46d4d8c533'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c337efb20d6d9f9bbb4746f6b119917af5c886dc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d1bc80da75c789f2f6830df89d91fb2f7a509943'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
epss: 0.00217
epssPercentile: 0.12127
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:47:38.082535Z'
ingestedAt: '2026-10-15T22:48:25.493Z'
---

## Overview

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

net_sched: sch_sfq: fix a potential crash on gso_skb handling

SFQ has an assumption of always being able to queue at least one packet.

However, after the blamed commit, sch->q.len can be inflated by packets
in sch->gso_skb, and an enqueue() on an empty SFQ qdisc can be followed
by an immediate drop.

Fix sfq_drop() to properly clear q->tail in this situation.


ip netns add lb
ip link add dev to-lb type veth peer name in-lb netns lb
ethtool -K to-lb tso off                 # force qdisc to requeue gso_skb
ip netns exec lb ethtool -K in-lb gro on # enable NAPI
ip link set dev to-lb up
ip -netns lb link set dev in-lb up
ip addr add dev to-lb 192.168.20.1/24
ip -netns lb addr add dev in-lb 192.168.20.2/24
tc qdisc replace dev to-lb root sfq limit 100

ip netns exec lb netserver

netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &

## Affected

- `linux_kernel >= 4.16, < 5.4.295`
- `linux_kernel >= 5.5, < 5.10.239`
- `linux_kernel >= 5.11, < 5.15.186`
- `linux_kernel >= 5.16, < 6.1.142`
- `linux_kernel >= 6.2, < 6.6.94`
- `linux_kernel >= 6.7, < 6.12.34`
- `linux_kernel >= 6.13, < 6.15.3`
- `linux_kernel = 6.16`
- `debian_linux = 11.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.15.3`