FKIE_CVE-2026-63993

Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-20 15:17
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() skb_tunnel_check_pmtu() can change skb->head. Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c. Found by Sashiko.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9257f56ac47ef1976bcd056cf986a9988eeec67a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a493efd4336cf19122ae0e4cbb3d31b32d70deea
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dc3bfa050f873371e745bdf478b1f5b738e5733d
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6b8bfce9d2f774d2c2243e0248e03efb99bba6c0",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "9257f56ac47ef1976bcd056cf986a9988eeec67a",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "8d435d68d71fb875876b722f4136caf74f2f48bd",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "dc3bfa050f873371e745bdf478b1f5b738e5733d",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "609e63312c29aad18026a1d3222e123d4b6b0feb",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "5303925e360527243b46a440a04667826bbc72b7",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "a493efd4336cf19122ae0e4cbb3d31b32d70deea",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "7d9ef0cb271555d8cf39fefe6c981e1493b25ecf",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.9"
            },
            {
              "lessThan": "5.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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",
  "lastModified": "2026-07-20T15:17:00.883",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T16:17:38.823",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9257f56ac47ef1976bcd056cf986a9988eeec67a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a493efd4336cf19122ae0e4cbb3d31b32d70deea"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dc3bfa050f873371e745bdf478b1f5b738e5733d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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