{"id":"CVE-2026-63829","summary":"net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink","details":"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-\u003enet. 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-\u003enet can rewrite a tunnel that\nlives in t-\u003enet.\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-\u003ecollect_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.","modified":"2026-07-22T05:30:06.551131146Z","published":"2026-07-19T12:02:23.191Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63829.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105"},{"type":"WEB","url":"https://git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63829.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63829"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"b57708add31494175be741ed3fd24023b50c3423"},{"fixed":"9831bc9ecb402957810c2045c663fbfe9b09e296"},{"fixed":"1697957eb0971d420dde42862b88eb43506a1105"},{"fixed":"47b5d3d506609b08b2e1f7c14f0b681a1953d572"},{"fixed":"8165f7ff57d9667d2bb477ef6af83ede7fed4ad7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63829.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.16.0"},{"fixed":"6.12.95"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.38"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63829.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}