CVE-2026-63829
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 0.13% probability · 3th percentile
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105
- https://git.kernel.org/stable/c/19275943d8fe903eb7b9aa53e380e41efd042ada
- https://git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572
- https://git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7
- https://git.kernel.org/stable/c/866b0f5ae599490bd496fd84581c68ac8b94e6af
- https://git.kernel.org/stable/c/92b766fc55156e0da2ecd0c2302c971118f8a229
- https://git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296
- https://git.kernel.org/stable/c/e54c05ed3d9c28733fb9e5837219aca3691defa3
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.