CVE intelligence

CVE-2026-52909

Vulnerability intelligence

Published Jun 19, 2026Sources checked Nov 12, 2026

7.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-52909 and is rated High severity with a CVSS score of 7.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Jul 8, 2026

CBL-Mariner Releases

Vendor-listed releases

6.6.144.1-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.1%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is 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.

Source: NVD