---
id: CVE-2026-97985
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  af_unix: Update last skb marker in manage_oob().

  Fahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU
  due to OOB skb.

  In the following cases, manage_oob(…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  af_unix: Update last skb marker in manage_oob().

  Fahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU
  due to OOB skb.

  In the following cases, manage_oob(…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 22dd70eb2c3d754862964377a75abafd3167346b <
    0630bfc773d85ac44da05b2c5a037dbbd39301ab
  - >-
    Linux >= 22dd70eb2c3d754862964377a75abafd3167346b <
    f1816b3d7ce80dcf086bb68ff5ae6e09520ca1fa
  - >-
    Linux >= 22dd70eb2c3d754862964377a75abafd3167346b <
    fc62a26493a98a0424d9dae2eb92a1daa1321f65
  - >-
    Linux >= 22dd70eb2c3d754862964377a75abafd3167346b <
    94fd4debd2e3a69cf93e766c8b328a810c228119
  - Linux ae3f9e1221b31b18dbd4c4b85d08574996bbd973
  - Linux ba0db4638525b8b054b3d546b45f7e473f477027
  - Linux 022d81a709cd553bbe2db8675f8e824f4aee6284
  - Linux 16dc252e7007547a7b72a2c21022ef81fb45e6a3
  - Linux >= 5.15.157 < 5.16
  - Linux >= 6.1.88 < 6.2
  - Linux >= 6.6.29 < 6.7
  - Linux >= 6.8.8 < 6.9
  - Linux 6.9
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:26.560'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97985'
references:
  - url: 'https://git.kernel.org/stable/c/0630bfc773d85ac44da05b2c5a037dbbd39301ab'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/94fd4debd2e3a69cf93e766c8b328a810c228119'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f1816b3d7ce80dcf086bb68ff5ae6e09520ca1fa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fc62a26493a98a0424d9dae2eb92a1daa1321f65'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.868Z'
---

## Overview

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

af_unix: Update last skb marker in manage_oob().

Fahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU
due to OOB skb.

In the following cases, manage_oob() skips OOB skb(s) and returns
NULL for the last recv(MSG_PEEK):

  socketpair(AF_UNIX, SOCK_STREAM, 0, sk);

  1) skb -> OOB skb -> NULL
     send(sk[0], "ab", 2, MSG_OOB);
     recv(sk[1], buf, 0, MSG_PEEK);

  2) skb -> consumed OOB skb -> NULL
     send(sk[0], "ab", 2, MSG_OOB);
     recv(sk[1], buf, 1, MSG_OOB);
     recv(sk[1], buf, 0, MSG_PEEK);

  3) consumed OOB skb -> OOB skb -> NULL
     send(sk[0], "a", 1, MSG_OOB);
     recv(sk[1], buf, 0, MSG_OOB);
     send(sk[0], "b", 1, MSG_OOB);
     recv(sk[1], buf, 1, MSG_PEEK);

Then, @copied is 0 in unix_stream_read_generic() (zero-length buffer,
or non-OOB skb is not yet consumed), and unix_stream_data_wait() is
called.

However, it returns immediately because @last is not updated in
unix_stream_read_generic(), and the thread busy-waits for a new skb.

Let's update @last in manage_oob().

For MSG_PEEK, @last is updated with the skipped OOB, and for the
non-peek case, @last matches the returned value (when !copied)
because OOB is unlinked.

Note that manage_oob() is inlined and no stack canary is added.

## Remediation

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