---
id: CVE-2026-99056
title: 'strparser: make sure __strp_recv isn''t running before tearing down the parser'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  strparser: make sure __strp_recv isn't running before tearing down the parser

  The comment above strp_done() claims that if strp is stopped,
  strp_recv will no longer be…
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 <
    a18dd388045dc7263d99a07db9de4e0f149ca8f1
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    9f3e9fe1b155e9b4572054d8d140586bc3512ecf
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    d2b5f637b9b67a79a50d42614d10653c13b4e449
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    eaa3a29004c063d7e9d5ea55636f693f67e6db0f
  - >-
    Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <
    0984ebc631792acf8fff105112ee74a6b8f1efcc
  - Linux 5.6
published: '2026-10-23'
updated: '2026-10-24'
sourceUpdated: '2026-10-24T14:10:15.756Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99056'
references:
  - url: 'https://git.kernel.org/stable/c/a18dd388045dc7263d99a07db9de4e0f149ca8f1'
  - url: 'https://git.kernel.org/stable/c/9f3e9fe1b155e9b4572054d8d140586bc3512ecf'
  - url: 'https://git.kernel.org/stable/c/d2b5f637b9b67a79a50d42614d10653c13b4e449'
  - url: 'https://git.kernel.org/stable/c/eaa3a29004c063d7e9d5ea55636f693f67e6db0f'
  - url: 'https://git.kernel.org/stable/c/0984ebc631792acf8fff105112ee74a6b8f1efcc'
tags:
  - cve.org
epss: 0.00209
epssPercentile: 0.10488
ingestedAt: '2026-10-23T13:24:55.521Z'
---

## Overview

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

strparser: make sure __strp_recv isn't running before tearing down the parser

The comment above strp_done() claims that if strp is stopped,
strp_recv will no longer be called. That's only true if the caller has
a mechanism (eg locking) to guarantee that strp_recv() calls that
started before strp_stop() have completed by the time we call
strp_done().

This adds a dummy lock_sock/release_sock pair to guarantee that any
in-flight strp_recv() (which runs under either bh_lock_sock or
lock_sock, depending if it's called from ->sk_data_ready or strp_work)
has completed.

Only espintcp can be affected by this race condition, but this patch
makes sure no future user of strp can have the bug.

This could crash on strp->sk ("general mode" of strp), but this mode
has been here for 9 years and has never been used. It'll be gone soon,
no point worrying about it.

Switch the stopped/paused/etc bits to u8's to avoid races between
strp_stop() and strp_pause/unpause().

A reproducer has been published and turns the possible UAF into an
exploit [1].

## Affected

- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < a18dd388045dc7263d99a07db9de4e0f149ca8f1`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 9f3e9fe1b155e9b4572054d8d140586bc3512ecf`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < d2b5f637b9b67a79a50d42614d10653c13b4e449`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < eaa3a29004c063d7e9d5ea55636f693f67e6db0f`
- `Linux >= e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 0984ebc631792acf8fff105112ee74a6b8f1efcc`
- `Linux 5.6`

## Remediation

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