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VulnerabilityPublished Updated

CVE-2026-52909: Linux kernel · ip6_vti: set netns_immutable on the fallback device.

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f4b6b4af7ef0661ac153c6f7eb1030aa8482c1a3 : patch Linux kernel soon.

Data as of 26 Oct 2026, 09:29 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f4b6b4af7ef0661ac153c6f7eb1030aa8482c1a3, ecf8904067dcba0dad86ece80874841e60317885, dcdce3bc9f08026ff3739ee7339e1bef526fc5f3 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < f4b6b4af7ef0661ac153c6f7eb1030aa8482c1a3
Fixed in
  • f4b6b4af7ef0661ac153c6f7eb1030aa8482c1a3
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < ecf8904067dcba0dad86ece80874841e60317885
Fixed in
  • ecf8904067dcba0dad86ece80874841e60317885
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < dcdce3bc9f08026ff3739ee7339e1bef526fc5f3
Fixed in
  • dcdce3bc9f08026ff3739ee7339e1bef526fc5f3
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < d289d5307762d1838aaece22c6b6fcad9e8865f9
Fixed in
  • d289d5307762d1838aaece22c6b6fcad9e8865f9
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < c5dbd669db5a426b3025512322e1bf2cdbe14305
Fixed in
  • c5dbd669db5a426b3025512322e1bf2cdbe14305
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < 12c65e2c7fef507551bd7b52123598a761662c01
Fixed in
  • 12c65e2c7fef507551bd7b52123598a761662c01

Description

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.

References

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