---
id: CVE-2026-89950
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  batman-adv: mcast: linearize skbuff for packet generation

  batadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only
  called (indirectly) by the unsharing+li…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  batman-adv: mcast: linearize skbuff for packet generation

  batadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only
  called (indirectly) by the unsharing+li…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 90039133221e33964ccb4a536dad7eb0a372fff7 <
    a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e
  - >-
    Linux >= 90039133221e33964ccb4a536dad7eb0a372fff7 <
    c32e5e25c41201c8c3b796a4ab2c45103187091e
  - >-
    Linux >= 90039133221e33964ccb4a536dad7eb0a372fff7 <
    2879177539e3ece483a8e5406970373698e9a6c5
  - >-
    Linux >= 90039133221e33964ccb4a536dad7eb0a372fff7 <
    6a30a59e2660afd03c975f1b8eae6a2301161197
  - Linux 6.8
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T11:17:05.160'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89950'
references:
  - url: 'https://git.kernel.org/stable/c/2879177539e3ece483a8e5406970373698e9a6c5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6a30a59e2660afd03c975f1b8eae6a2301161197'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c32e5e25c41201c8c3b796a4ab2c45103187091e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T10:53:53.963Z'
epss: 0.002
epssPercentile: 0.10167
---

## Overview

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

batman-adv: mcast: linearize skbuff for packet generation

batadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only
called (indirectly) by the unsharing+linearizing batadv_recv_mcast_packet()
handler. When it is called (indirectly) by batadv_mcast_forw_mcsend() then
it will be unshared but not linearized. The SKB_LINEAR_ASSERT() can
therefore cause a fatal BUG().

The linearization should happen during the expansion of the head because
the scrape function can be hit already during the initial
batadv_mcast_forw_mode() selection code:

* batadv_interface_tx
* batadv_mcast_forw_mode
* batadv_mcast_forw_mode_by_count()
* batadv_mcast_forw_push()
  -> calls batadv_mcast_forw_expand_head() before everything else
* batadv_mcast_forw_push_tvlvs()
* batadv_mcast_forw_push_dests()
* batadv_mcast_forw_push_adjust_padding()
* batadv_mcast_forw_scrape()

## Remediation

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