---
id: CVE-2026-31518
title: 'esp: fix skb leak with espintcp and async crypto'
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: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    aca3ad0c262f54a5b5c95dda80a48365997d1224
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    41aafca57de4a4c026701622bd4648f112a9edcd
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    4820847e036ff1035b01b69ad68dfc17e7028fe9
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    6a3ec6efbc4f90e0ccb2e71574f07351f19996f4
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    df6f995358dc1f3c42484f5cfe241d7bd3e1cd15
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    88d386243ed374ac969dabd3bbc1409a31d81818
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    6aa9841d917532d0f2d932d1ff2f3a94305aaf47
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    0c0eef8ccd2413b0a10eb6bbd3442333b1e64dd2
  - Linux 5.6
published: '2026-04-22'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T08:47:37.244Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-31518'
references:
  - url: 'https://git.kernel.org/stable/c/aca3ad0c262f54a5b5c95dda80a48365997d1224'
  - url: 'https://git.kernel.org/stable/c/41aafca57de4a4c026701622bd4648f112a9edcd'
  - url: 'https://git.kernel.org/stable/c/4820847e036ff1035b01b69ad68dfc17e7028fe9'
  - url: 'https://git.kernel.org/stable/c/6a3ec6efbc4f90e0ccb2e71574f07351f19996f4'
  - url: 'https://git.kernel.org/stable/c/df6f995358dc1f3c42484f5cfe241d7bd3e1cd15'
  - url: 'https://git.kernel.org/stable/c/88d386243ed374ac969dabd3bbc1409a31d81818'
  - url: 'https://git.kernel.org/stable/c/6aa9841d917532d0f2d932d1ff2f3a94305aaf47'
  - url: 'https://git.kernel.org/stable/c/0c0eef8ccd2413b0a10eb6bbd3442333b1e64dd2'
tags:
  - cve.org
epss: 0.00171
epssPercentile: 0.05675
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 >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < aca3ad0c262f54a5b5c95dda80a48365997d1224`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 41aafca57de4a4c026701622bd4648f112a9edcd`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 4820847e036ff1035b01b69ad68dfc17e7028fe9`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 6a3ec6efbc4f90e0ccb2e71574f07351f19996f4`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < df6f995358dc1f3c42484f5cfe241d7bd3e1cd15`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 88d386243ed374ac969dabd3bbc1409a31d81818`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 6aa9841d917532d0f2d932d1ff2f3a94305aaf47`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 0c0eef8ccd2413b0a10eb6bbd3442333b1e64dd2`
- `Linux 5.6`

## Remediation

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