CVE-2026-52909
Received Received - Intake
ip6_vti Fallback Device Netns Immutable Flag Missing

Publication date: 2026-06-19

Last updated on: 2026-06-19

Assigner: kernel.org

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.
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Meta Information
Published
2026-06-19
Last Modified
2026-06-19
Generated
2026-06-19
AI Q&A
2026-06-19
EPSS Evaluated
N/A
NVD
CVE-2026-52909
EUVD
EUVD-2026-38033
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
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Exploitability
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KEV
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's handling of the ip6_vti (IPv6 Virtual Tunnel Interface). Specifically, the function vti6_init_net() does not set the netns_immutable flag on the per-network namespace fallback tunnel device (ip6_vti0).

Other similar tunnel drivers such as ip6_tunnel, sit, ip6_gre, and ip_tunnel correctly set this flag during their fallback device initialization. The netns_immutable flag prevents the fallback device from being moved to another network namespace.

Because ip6_vti0 did not have this flag set, it could potentially be moved between network namespaces, which is unintended behavior and considered a vulnerability.

Impact Analysis

The vulnerability could allow the fallback tunnel device (ip6_vti0) to be moved to a different network namespace than intended. This could lead to unexpected network behavior or security issues related to network isolation.

Since network namespaces are used to isolate network environments, the ability to move a device between namespaces could undermine this isolation, potentially allowing unauthorized access or interference between network namespaces.

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