{"api_version":"1","generated_at":"2026-07-23T10:04:22+00:00","cve":"CVE-2026-63992","urls":{"html":"https://cve.report/CVE-2026-63992","api":"https://cve.report/api/cve/CVE-2026-63992.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63992","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63992"},"summary":{"title":"tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()","description":"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->transport_header))~0U is 65535.\n\nAccess the icmp header based on IPv4 network header,\nafter making sure icmp->type is present in skb linear part.\n\nNote that iptunnel_pmtud_check_icmpv6()) is fine.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:38","updated_at":"2026-07-20 15:17:00"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":9.1,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","data":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec","name":"https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c","name":"https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e","name":"https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d","name":"https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7","name":"https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93","name":"https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4","name":"https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c","name":"https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63992","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63992","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 5a92cb45e34749865d03daf8d3500f77b5f6644c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f c7b7ec3e69e673c0d6b57f74d21da50c485c598e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 7f4f7efe7f30edd29c4988de01728bf2398217e4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"63992","cve":"CVE-2026-63992","epss":"0.001760000","percentile":"0.073840000","score_date":"2026-07-20","updated_at":"2026-07-21 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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->transport_header))~0U is 65535.\n\nAccess the icmp header based on IPv4 network header,\nafter making sure icmp->type is present in skb linear part.\n\nNote that iptunnel_pmtud_check_icmpv6()) is fine."}],"metrics":[{"cvssV3_1":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-20T13:42:07.956Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c"},{"url":"https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e"},{"url":"https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4"},{"url":"https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec"},{"url":"https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7"},{"url":"https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93"},{"url":"https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c"},{"url":"https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d"}],"title":"tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63992","datePublished":"2026-07-19T14:56:12.528Z","dateReserved":"2026-07-19T07:54:57.025Z","dateUpdated":"2026-07-20T13:42:07.956Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:38","lastModifiedDate":"2026-07-20 15:17:00","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":9.1,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63992","Ordinal":"1","Title":"tunnels: do not assume transport header in iptunnel_pmtud_check_","CVE":"CVE-2026-63992","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63992","Ordinal":"1","NoteData":"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->transport_header))~0U is 65535.\n\nAccess the icmp header based on IPv4 network header,\nafter making sure icmp->type is present in skb linear part.\n\nNote that iptunnel_pmtud_check_icmpv6()) is fine.","Type":"Description","Title":"tunnels: do not assume transport header in iptunnel_pmtud_check_"}]}}}