Bug 2516421 (CVE-2026-72055)

Summary: CVE-2026-72055 kernel: net: ip6_vti: require CAP_NET_ADMIN in the device netns for changelink
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `ip6_vti` component, which handles IPv6 Virtual Tunnel Interfaces. A local attacker with certain network administration privileges in one isolated network environment (network namespace) could exploit this vulnerability. This allows them to modify the configuration of a tunnel in a different isolated network environment where they do not have full administrative rights, potentially leading to unauthorized network changes or the redirection of network traffic.
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Description OSIDB Bzimport 2026-08-15 06:11:41 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: ip6_vti: require CAP_NET_ADMIN in the device netns for changelink

vti6_changelink() operates on at most two netns, dev_net(dev) and the
tunnel link netns t->net. They differ once the device is created in or
moved to a netns other than the one the request runs in. The rtnl
changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
caller privileged there but not in t->net can rewrite a tunnel that
lives in t->net.

Gate vti6_changelink() on rtnl_dev_link_net_capable() at its top,
before any attribute is parsed.
Comment 1 Keith Grant 2026-08-17 18:41:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081516-CVE-2026-72055-41c4@gregkh/T