---
id: CVE-2025-21926
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: gso: fix ownership in __udp_gso_segment

  In __udp_gso_segment the skb destructor is removed before segmenting the
  skb but the socket reference is kept as-is
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: gso: fix ownership in __udp_gso_segment

  In __udp_gso_segment the skb destructor is removed before segmenting the
  skb but the socket reference is kept as-is. This …
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 4.18, < 5.4.291'
  - 'linux_kernel >= 5.5, < 5.10.235'
  - 'linux_kernel >= 5.11, < 5.15.179'
  - 'linux_kernel >= 5.16, < 6.1.131'
  - 'linux_kernel >= 6.2, < 6.6.83'
  - 'linux_kernel >= 6.7, < 6.12.19'
  - 'linux_kernel >= 6.13, < 6.13.7'
  - linux_kernel = 6.14
patched:
  - linux_kernel 6.13.7
published: '2025-04-01'
updated: '2026-07-14'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-21926'
references:
  - url: 'https://git.kernel.org/stable/c/01a83237644d6822bc7df2c5564fc81b0df84358'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/084819b0d8b1bd433b90142371eb9450d657f8ca'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/455217ac9db0cf9349b3933664355e907bb1a569'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9f28205ddb76e86cac418332e952241d85fed0dc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a2d1cca955ed34873e524cc2e6e885450d262f05'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e8db70537878e1bb3fd83e5abcc6feefc0587828'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ee01b2f2d7d0010787c2343463965bbc283a497f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00239
epssPercentile: 0.13316
ingestedAt: '2026-07-14T13:36:56.091Z'
---

## Overview

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

net: gso: fix ownership in __udp_gso_segment

In __udp_gso_segment the skb destructor is removed before segmenting the
skb but the socket reference is kept as-is. This is an issue if the
original skb is later orphaned as we can hit the following bug:

  kernel BUG at ./include/linux/skbuff.h:3312!  (skb_orphan)
  RIP: 0010:ip_rcv_core+0x8b2/0xca0
  Call Trace:
   ip_rcv+0xab/0x6e0
   __netif_receive_skb_one_core+0x168/0x1b0
   process_backlog+0x384/0x1100
   __napi_poll.constprop.0+0xa1/0x370
   net_rx_action+0x925/0xe50

The above can happen following a sequence of events when using
OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an
OVS_ACTION_ATTR_OUTPUT action:

1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb
   goes through queue_gso_packets and then __udp_gso_segment, where its
   destructor is removed.
2. The segments' data are copied and sent to userspace.
3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the
   same original skb is sent to its path.
4. If it later hits skb_orphan, we hit the bug.

Fix this by also removing the reference to the socket in
__udp_gso_segment.

## Affected

- `linux_kernel >= 4.18, < 5.4.291`
- `linux_kernel >= 5.5, < 5.10.235`
- `linux_kernel >= 5.11, < 5.15.179`
- `linux_kernel >= 5.16, < 6.1.131`
- `linux_kernel >= 6.2, < 6.6.83`
- `linux_kernel >= 6.7, < 6.12.19`
- `linux_kernel >= 6.13, < 6.13.7`
- `linux_kernel = 6.14`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.13.7`