{"id":"CVE-2026-63917","title":"ip6: vti: Use ip6_tnl.net in vti6_changelink().","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nip6: vti: Use ip6_tnl.net in vti6_changelink().\n\nip netns add ns1\nip netns add ns2\nip -n ns1 link add vti6_test type vti6 remote ::1 local ::2 key 7\nip -n ns1 link set …","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","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < 0cdce7618464f7fb06f461e8f4ad575cb1d570f4","Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < f5c68875e25f331e497ddfbe81e2d8163a87f136","Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < d9c5eecdb3c740e65038651db7c686b10d76d1bc","Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < f1e89a943ee574d0f2f16246eb3f2d7330fdeb03","Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < 225b467e3b631f38be22e4b38062a1fed02fdd21","Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < fc32be9ac2788524c6b24efd681cce7a6e731a92","Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < ee1778ba0f5cb53be771f97017d01eb356c797bf","Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < 11b326fb0a374f4654f9be22d0f0f7abd9f7d3fe","Linux 3.15"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:33:18.521375Z"},"published":"2026-07-19","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:42:11.412Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63917","references":[{"url":"https://git.kernel.org/stable/c/0cdce7618464f7fb06f461e8f4ad575cb1d570f4"},{"url":"https://git.kernel.org/stable/c/f5c68875e25f331e497ddfbe81e2d8163a87f136"},{"url":"https://git.kernel.org/stable/c/d9c5eecdb3c740e65038651db7c686b10d76d1bc"},{"url":"https://git.kernel.org/stable/c/f1e89a943ee574d0f2f16246eb3f2d7330fdeb03"},{"url":"https://git.kernel.org/stable/c/225b467e3b631f38be22e4b38062a1fed02fdd21"},{"url":"https://git.kernel.org/stable/c/fc32be9ac2788524c6b24efd681cce7a6e731a92"},{"url":"https://git.kernel.org/stable/c/ee1778ba0f5cb53be771f97017d01eb356c797bf"},{"url":"https://git.kernel.org/stable/c/11b326fb0a374f4654f9be22d0f0f7abd9f7d3fe"}],"tags":["cve.org"],"epss":0.00169,"epssPercentile":0.05791,"ingestedAt":"2026-10-16T17:24:46.775Z","slug":"CVE-2026-63917","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nip6: vti: Use ip6_tnl.net in vti6_changelink().\n\nip netns add ns1\nip netns add ns2\nip -n ns1 link add vti6_test type vti6 remote ::1 local ::2 key 7\nip -n ns1 link set vti6_test netns ns2\nip -n ns2 link set vti6_test type vti6 remote ::3 local ::4 key 9\nip netns del ns2\nip netns del ns1\n[  132.495484] ------------[ cut here ]------------\n[  132.497609] kernel BUG at net/core/dev.c:12376!\n\nCommit 61220ab34948 (\"vti6: Enable namespace changing\") dropped\nNETIF_F_NETNS_LOCAL from vti6 devices. A vti6 tunnel can then\nmove through IFLA_NET_NS_FD. After the move dev_net(dev) points\nat the new netns while t->net stays at the creation netns.\n\nvti6_changelink() and vti6_update() still use dev_net(dev) and\ndev_net(t->dev). They unlink from one per netns hash and relink\ninto another. The creation netns is left with a stale entry.\ncleanup_net() of that netns later walks freed memory.\n\nReachable from an unprivileged user namespace (unshare --user\n--map-root-user --net). Cross tenant scope on container hosts.\n\n## Affected\n\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < 0cdce7618464f7fb06f461e8f4ad575cb1d570f4`\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < f5c68875e25f331e497ddfbe81e2d8163a87f136`\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < d9c5eecdb3c740e65038651db7c686b10d76d1bc`\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < f1e89a943ee574d0f2f16246eb3f2d7330fdeb03`\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < 225b467e3b631f38be22e4b38062a1fed02fdd21`\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < fc32be9ac2788524c6b24efd681cce7a6e731a92`\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < ee1778ba0f5cb53be771f97017d01eb356c797bf`\n- `Linux >= 61220ab349485d911083d0b7990ccd3db6c63297 < 11b326fb0a374f4654f9be22d0f0f7abd9f7d3fe`\n- `Linux 3.15`\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":[]}