---
id: CVE-2026-52909
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ip6_vti: set netns_immutable on the fallback device.

  john1988 and Noam Rathaus reported that vti6_init_net() does not set the
  netns_immutable flag on the per-netns fal…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ip6_vti: set netns_immutable on the fallback device.

  john1988 and Noam Rathaus reported that vti6_init_net() does not set the
  netns_immutable flag on the per-netns fal…
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'
published: '2026-06-19'
updated: '2026-07-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-52909'
references:
  - url: 'https://git.kernel.org/stable/c/12acc977838c943636fb01e2f3087d2e4cc3b7cc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/12c65e2c7fef507551bd7b52123598a761662c01'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7f28e3948c59481f8db9c9638e204258d26b4e41'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c5dbd669db5a426b3025512322e1bf2cdbe14305'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d289d5307762d1838aaece22c6b6fcad9e8865f9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dcdce3bc9f08026ff3739ee7339e1bef526fc5f3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ecf8904067dcba0dad86ece80874841e60317885'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f4b6b4af7ef0661ac153c6f7eb1030aa8482c1a3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.0012
epssPercentile: 0.01633
ingestedAt: '2026-07-04T12:56:09.602Z'
---

## Overview

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

ip6_vti: set netns_immutable on the fallback device.

john1988 and Noam Rathaus reported that vti6_init_net() does not set the
netns_immutable flag on the per-netns fallback tunnel device (ip6_vti0).

Other similar tunnel drivers (like ip6_tunnel, sit, ip6_gre, and ip_tunnel)
correctly set this flag during their fallback device initialization to
prevent them from being moved to another network namespace.

## Remediation

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