CVE-2026-63829
Description
In the Linux kernel, the following vulnerability has been resolved: net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink A tunnel 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. Add rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in net/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is skipped when the link netns is dev_net(dev), where the rtnl path already checked it. The other patches in this series use the same helper. Gate ipgre_changelink() and erspan_changelink() with it, at the top of the op before any attribute is parsed, because the parsers update live tunnel fields first. ipgre_netlink_parms() sets t->collect_md before ip_tunnel_changelink() runs. Commit 8b484efd5cb4 ("ip6: vti: Use ip6_tnl.net in vti6_siocdevprivate().") added the same check on the ioctl path. This adds it on RTM_NEWLINK.
How to fix
- linux linux_kernel5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 3.16 ≤ v < 5.10.261, 5.11 ≤ v < 5.15.212, 5.16 ≤ v < 6.1.178, 6.2 ≤ v < 6.6.145, 6.7 ≤ v < 6.12.95, 6.13 ≤ v < 6.18.38, 6.19 ≤ v < 7.1.3 | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3 |
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