CVE-2026-52909
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.
Affected versions
Linux kernel versions
3.15
and later are affected. Fixed in
6.18.36,
7.0.13,
7.1
and their respective stable series.
References
3 totalFrequently asked questions
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What is CVE-2026-52909?
CVE-2026-52909 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 3.15 onward and has been patched in 6.18.36, 7.0.13 and 7.1. CVE-2026-52909 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-52909?
Yes — CVE-2026-52909 has been patched. Fixed versions include 6.18.36, 7.0.13 and 7.1. If you are running Linux kernel 3.15 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-52909 actively exploited?
No — CVE-2026-52909 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.