{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f"
            },
            {
              "fixed": "6b8bfce9d2f774d2c2243e0248e03efb99bba6c0"
            },
            {
              "fixed": "9257f56ac47ef1976bcd056cf986a9988eeec67a"
            },
            {
              "fixed": "8d435d68d71fb875876b722f4136caf74f2f48bd"
            },
            {
              "fixed": "dc3bfa050f873371e745bdf478b1f5b738e5733d"
            },
            {
              "fixed": "609e63312c29aad18026a1d3222e123d4b6b0feb"
            },
            {
              "fixed": "5303925e360527243b46a440a04667826bbc72b7"
            },
            {
              "fixed": "a493efd4336cf19122ae0e4cbb3d31b32d70deea"
            },
            {
              "fixed": "7d9ef0cb271555d8cf39fefe6c981e1493b25ecf"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "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"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63993.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()\n\nskb_tunnel_check_pmtu() can change skb-\u003ehead.\n\nReusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF.\n\nUse instead ip_hdr(skb) as done in drivers/net/bareudp.c\nand drivers/net/geneve.c.\n\nFound by Sashiko.",
  "id": "CVE-2026-63993",
  "modified": "2026-07-22T05:29:45.068888945Z",
  "published": "2026-07-19T14:56:13.218Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9257f56ac47ef1976bcd056cf986a9988eeec67a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a493efd4336cf19122ae0e4cbb3d31b32d70deea"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dc3bfa050f873371e745bdf478b1f5b738e5733d"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63993.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63993"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()"
}