{"cve":"CVE-2026-63994","nvd":{"published":"2026-07-19T16:17:38.943","modified":"2026-10-19T21:17:17.343","status":"Modified","description":"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->head.\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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/50750d86a2e5266aba0c295483b3397843198b11","https://git.kernel.org/stable/c/6dff77899b9e9fe5d854abda3a98ad04e7229ef7","https://git.kernel.org/stable/c/7254aef4d1a7e18e887af9010e2f2dc34806789b","https://git.kernel.org/stable/c/76cd9398a0470257ab765bdf5f358a2af2e17934","https://git.kernel.org/stable/c/95b6d772bfe788331d9742d73eaa12e113b2adc4"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2026-63994","score":0.00514,"percentile":0.43527,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}