{"id":"CVE-2026-63829","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ip_gre: require CAP_NET_ADMIN in the device netns for changelink\n\nA tunnel changelink() operates on at most two netns, dev_net(dev) and\nthe tunnel link netns t->ne…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ip_gre: require CAP_NET_ADMIN in the device netns for changelink\n\nA tunnel changelink() operates on at most two netns, dev_net(dev) and\nthe tunnel link netns t->ne…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","published":"2026-07-19","updated":"2026-08-17","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-63829","references":[{"url":"https://git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/19275943d8fe903eb7b9aa53e380e41efd042ada","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/866b0f5ae599490bd496fd84581c68ac8b94e6af","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/92b766fc55156e0da2ecd0c2302c971118f8a229","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e54c05ed3d9c28733fb9e5837219aca3691defa3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00127,"epssPercentile":0.0201,"ingestedAt":"2026-08-17T05:47:50.343Z","slug":"CVE-2026-63829","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: ip_gre: require CAP_NET_ADMIN in the device netns for changelink\n\nA tunnel changelink() operates on at most two netns, dev_net(dev) and\nthe tunnel link netns t->net. They differ once the device is created in\nor moved to a netns other than the one the request runs in. The rtnl\nchangelink path checks CAP_NET_ADMIN only against dev_net(dev), so a\ncaller privileged there but not in t->net can rewrite a tunnel that\nlives in t->net.\n\nAdd rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in\nnet/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is\nskipped when the link netns is dev_net(dev), where the rtnl path already\nchecked it. The other patches in this series use the same helper.\n\nGate ipgre_changelink() and erspan_changelink() with it, at the top of\nthe op before any attribute is parsed, because the parsers update live\ntunnel fields first. ipgre_netlink_parms() sets t->collect_md before\nip_tunnel_changelink() runs.\n\nCommit 8b484efd5cb4 (\"ip6: vti: Use ip6_tnl.net in\nvti6_siocdevprivate().\") added the same check on the ioctl path. This\nadds it on RTM_NEWLINK.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}