Live › vulnerability › CVE-2026-98569
Go to dashboardThe Linux kernel let an existing GRE, GRETAP or ERSPAN device be switched to metadata (collect_md) mode through changelink, which skipped the uniqueness check that newlink enforces. Converting one device can overwrite and later clear the shared metadata receive entry of another device in the same network namespace, breaking tunnel receive for the surviving device.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Hosts that run the Linux kernel with GRE, GRETAP or ERSPAN tunnels, typically routers, hypervisors or hosts using tunnel overlays, where an administrator or a process with network admin rights changes tunnel modes. Systems without GRE, GRETAP or ERSPAN devices, or that do not change tunnel modes after creation, are unlikely to be affected.
No product ranges from the sources yet.
uname -r and compare against the fixed kernel versions listed by the vendor or NVD entry (unknown in the sources).ip -d link show type gre and ip -d link show type gretap and look for external or collect_metadata on tunnels.ip -d link show type erspan to check ERSPAN devices.ip link set ... external style changes and recreate them instead.Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
ip_gre: Reject enabling collect metadata through changelink
ipgre_netlink_parms() can enable collect_md on an existing GRE, GRETAP or ERSPAN device. Unlike newlink, changelink does not enforce metadata tunnel uniqueness. Converting a non-metadata device can therefore replace the metadata receive entry for another device of the same type in the same netns. Deleting either device then clears the shared entry, breaking metadata receive lookup for the surviving device.
If parameter validation fails after collect_md is set, deleting the modified device can also clear an entry it never owned.
Reject enabling metadata mode in both changelink callbacks before any encapsulation or tunnel parameters are modified. Allow requests that repeat the metadata attribute on an existing metadata device.
This page as .md · .json · in your agent: get_signal("CVE-2026-98569")
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