{"id":"CVE-2026-63994","summary":"tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()\n\nSashiko found that iptunnel_pmtud_build_icmp() and\niptunnel_pmtud_build_icmpv6() were caching ip_hdr() and ipv6_hdr()\nbefore an skb_cow() call which can reallocate skb-\u003ehead.\n\nFix this possible UAF by initializing the local variables\nafter the skb_cow() call.\n\nRemove skb_reset_network_header() calls which were not needed.","modified":"2026-07-22T05:30:07.588610205Z","published":"2026-07-19T14:56:13.896Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63994.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/50750d86a2e5266aba0c295483b3397843198b11"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6dff77899b9e9fe5d854abda3a98ad04e7229ef7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7254aef4d1a7e18e887af9010e2f2dc34806789b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/76cd9398a0470257ab765bdf5f358a2af2e17934"},{"type":"WEB","url":"https://git.kernel.org/stable/c/95b6d772bfe788331d9742d73eaa12e113b2adc4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b4bc94353050b1fa7b702bd4c6600710dd926cff"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bf8b3f34c37c162357138e7c0942723b8b94fed1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f3f204541f280a6ecb04503a0d6794d93990ca43"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63994.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63994"},{"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":"95b6d772bfe788331d9742d73eaa12e113b2adc4"},{"fixed":"7254aef4d1a7e18e887af9010e2f2dc34806789b"},{"fixed":"bf8b3f34c37c162357138e7c0942723b8b94fed1"},{"fixed":"76cd9398a0470257ab765bdf5f358a2af2e17934"},{"fixed":"50750d86a2e5266aba0c295483b3397843198b11"},{"fixed":"6dff77899b9e9fe5d854abda3a98ad04e7229ef7"},{"fixed":"f3f204541f280a6ecb04503a0d6794d93990ca43"},{"fixed":"b4bc94353050b1fa7b702bd4c6600710dd926cff"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63994.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-2026-63994.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:H/A:H"}]}