{"id":"CVE-2026-63992","summary":"tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntunnels: do not assume transport header in iptunnel_pmtud_check_icmp()\n\nIn some cases, iptunnel_pmtud_check_icmp() can be called while\nskb transport header is not set.\n\nThis triggers an out-of-bound access, because\n(typeof(skb-\u003etransport_header))~0U is 65535.\n\nAccess the icmp header based on IPv4 network header,\nafter making sure icmp-\u003etype is present in skb linear part.\n\nNote that iptunnel_pmtud_check_icmpv6()) is fine.","modified":"2026-07-22T05:29:59.708125709Z","published":"2026-07-19T14:56:12.528Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63992.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93"},{"type":"WEB","url":"https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63992.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63992"},{"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":"4cb47a8644cc9eb8ec81190a50e79e6530d0297f"},{"fixed":"5a92cb45e34749865d03daf8d3500f77b5f6644c"},{"fixed":"c7b7ec3e69e673c0d6b57f74d21da50c485c598e"},{"fixed":"7f4f7efe7f30edd29c4988de01728bf2398217e4"},{"fixed":"e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec"},{"fixed":"a096b6e34f602950af9a2b0856cd93a5f4c276d7"},{"fixed":"43368636c663cff6e59dde93cf4b8e43ac28eb93"},{"fixed":"cb549df9ce4ee15c9d5b19ddab12cf2128e4313c"},{"fixed":"509323077ef79a26ba0c60bb556e45c12c398b2d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63992.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.9.0"},{"fixed":"5.10.259"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.210"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.176"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.143"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.93"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.35"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63992.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"}]}