---
id: CVE-2026-52935
title: 'xfrm: espintcp: do not reuse an in-progress partial send'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xfrm: espintcp: do not reuse an in-progress partial send

  espintcp keeps a single in-flight transmit in ctx->partial.
  Before building a new sk_msg, espintcp_sendmsg() f…
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 >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    6564e9c7af7e1dc7bfe7f3093b728abe484d7630
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    1777ceac4bea5e568a5ad44b7f9bb219c1db21b6
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    8c6c691bf062dc0753a139a4ab8cb92a70fcf8f3
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    aa82a078f70f7ff88ba7d1017134e79d1ac140f2
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    ba21439302db9a82fe4edbed1e38a97271529421
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    f9b38a8fbfa07f1deaf7ee1eb38fa8b21ea13990
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    37487d55bf3300e3d2c1368da5c2bd3e3834ea4f
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    c381039ade2e161ab08c0eda73c4f8b9a7115928
  - Linux 5.6
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:23:01.117587Z'
published: '2026-06-24'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:31:20.919Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-52935'
references:
  - url: 'https://git.kernel.org/stable/c/6564e9c7af7e1dc7bfe7f3093b728abe484d7630'
  - url: 'https://git.kernel.org/stable/c/1777ceac4bea5e568a5ad44b7f9bb219c1db21b6'
  - url: 'https://git.kernel.org/stable/c/8c6c691bf062dc0753a139a4ab8cb92a70fcf8f3'
  - url: 'https://git.kernel.org/stable/c/aa82a078f70f7ff88ba7d1017134e79d1ac140f2'
  - url: 'https://git.kernel.org/stable/c/ba21439302db9a82fe4edbed1e38a97271529421'
  - url: 'https://git.kernel.org/stable/c/f9b38a8fbfa07f1deaf7ee1eb38fa8b21ea13990'
  - url: 'https://git.kernel.org/stable/c/37487d55bf3300e3d2c1368da5c2bd3e3834ea4f'
  - url: 'https://git.kernel.org/stable/c/c381039ade2e161ab08c0eda73c4f8b9a7115928'
tags:
  - cve.org
epss: 0.0012
epssPercentile: 0.01714
ingestedAt: '2026-10-16T17:24:46.721Z'
---

## Overview

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

xfrm: espintcp: do not reuse an in-progress partial send

espintcp keeps a single in-flight transmit in ctx->partial.
Before building a new sk_msg, espintcp_sendmsg() first tries to flush
that state through espintcp_push_msgs().

For blocking callers, espintcp_push_msgs() may return success even when
the previous partial send is still pending. espintcp_sendmsg() would
then reinitialize emsg->skmsg and reuse ctx->partial while the old
transfer still owns that state.

Do not rebuild the send message when ctx->partial is still in progress.
If espintcp_push_msgs() returns with emsg->len still set, fail the new
send instead of overwriting the live partial state.

This is a memory-safety fix: reusing the live partial-send state can
leave a stale offset attached to a new sk_msg and lead to an out-of-
bounds read in the send path.

tcp_sendmsg_locked() already handles waiting for send buffer memory, so
the fix here is just to preserve espintcp's one-message-at-a-time
transmit state.

## Affected

- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 6564e9c7af7e1dc7bfe7f3093b728abe484d7630`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 1777ceac4bea5e568a5ad44b7f9bb219c1db21b6`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 8c6c691bf062dc0753a139a4ab8cb92a70fcf8f3`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < aa82a078f70f7ff88ba7d1017134e79d1ac140f2`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < ba21439302db9a82fe4edbed1e38a97271529421`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < f9b38a8fbfa07f1deaf7ee1eb38fa8b21ea13990`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 37487d55bf3300e3d2c1368da5c2bd3e3834ea4f`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < c381039ade2e161ab08c0eda73c4f8b9a7115928`
- `Linux 5.6`

## Remediation

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