Bug 2516306 (CVE-2026-72052)

Summary: CVE-2026-72052 kernel: net: ip6_gre: 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: high Docs Contact:
Priority: high    
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_gre` and `ip6erspan` tunnel drivers. The `changelink` functions in these drivers do not adequately verify administrative capabilities (`CAP_NET_ADMIN`) across different network namespaces. This allows a local attacker, who has `CAP_NET_ADMIN` in one network namespace but not in the tunnel's network namespace, to modify the tunnel's configuration. This could lead to unauthorized changes to network tunnel settings.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-15 06:05:35 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: ip6_gre: require CAP_NET_ADMIN in the device netns for changelink

ip6gre_changelink() and ip6erspan_changelink() operate 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 both ops on rtnl_dev_link_net_capable() at their top, before any
attribute is parsed.
Comment 1 Keith Grant 2026-08-17 18:18:42 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081515-CVE-2026-72052-1653@gregkh/T