---
id: CVE-2026-31518
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  esp: fix skb leak with espintcp and async crypto

  When the TX queue for espintcp is full, esp_output_tail_tcp will
  return an error and not free the skb, because with sy…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  esp: fix skb leak with espintcp and async crypto

  When the TX queue for espintcp is full, esp_output_tail_tcp will
  return an error and not free the skb, because with sy…
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'
cwe:
  - CWE-401
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.6, < 5.10.253'
  - 'linux_kernel >= 5.11, < 5.15.203'
  - 'linux_kernel >= 5.16, < 6.1.168'
  - 'linux_kernel >= 6.2, < 6.6.131'
  - 'linux_kernel >= 6.7, < 6.12.80'
  - 'linux_kernel >= 6.13, < 6.18.21'
  - 'linux_kernel >= 6.19, < 6.19.11'
  - linux_kernel = 7.0
patched:
  - linux_kernel 6.19.11
published: '2026-04-22'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:09.963'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31518'
references:
  - url: 'https://git.kernel.org/stable/c/0c0eef8ccd2413b0a10eb6bbd3442333b1e64dd2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/41aafca57de4a4c026701622bd4648f112a9edcd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4820847e036ff1035b01b69ad68dfc17e7028fe9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6a3ec6efbc4f90e0ccb2e71574f07351f19996f4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6aa9841d917532d0f2d932d1ff2f3a94305aaf47'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/88d386243ed374ac969dabd3bbc1409a31d81818'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/aca3ad0c262f54a5b5c95dda80a48365997d1224'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/df6f995358dc1f3c42484f5cfe241d7bd3e1cd15'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-082556.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-457936.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00129
epssPercentile: 0.02499
ingestedAt: '2026-09-08T15:33:26.990Z'
---

## Overview

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

esp: fix skb leak with espintcp and async crypto

When the TX queue for espintcp is full, esp_output_tail_tcp will
return an error and not free the skb, because with synchronous crypto,
the common xfrm output code will drop the packet for us.

With async crypto (esp_output_done), we need to drop the skb when
esp_output_tail_tcp returns an error.

## Affected

- `linux_kernel >= 5.6, < 5.10.253`
- `linux_kernel >= 5.11, < 5.15.203`
- `linux_kernel >= 5.16, < 6.1.168`
- `linux_kernel >= 6.2, < 6.6.131`
- `linux_kernel >= 6.7, < 6.12.80`
- `linux_kernel >= 6.13, < 6.18.21`
- `linux_kernel >= 6.19, < 6.19.11`
- `linux_kernel = 7.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.11`