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CVE-2026-52909VulnerabilityPublished Updated

Microsoft · ip6_vti: set netns_immutable on the fallback device

Affects MicrosoftSource GCVE Database

0
Authoritative record:CVE-2026-52909· High 7.8

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

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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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