{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63992", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.025Z", "datePublished": "2026-07-19T14:56:12.528Z", "dateUpdated": "2026-08-05T12:37:55.661Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:37:55.661Z"}, "descriptions": [{"lang": "en", "value": "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."}], "metrics": [{"cvssV3_1": {"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"}, "scenarios": [{"lang": "en", "value": "AV:N - The vulnerable code runs on the VXLAN/GENEVE transmit path when processing remotely received UDP-encapsulated tunnel traffic (or L2 frames forwarded through a bridge port), which is reachable by sending crafted packets over the network to the victim VTEP.\nAC:L - The attacker fully controls the inner IPv4 header fields (DF bit, length, addresses) and can reliably craft oversized packets that exceed the tunnel-adjusted PMTU on bridge-port tunnel devices without depending on race timing or uncontrollable system state.\nPR:N - Exploitation requires only the ability to send network packets to a host with VXLAN/GENEVE bridged; no local account, authentication, or capabilities on the victim are needed.\nUI:N - No victim user action is required; the kernel processes attacker-supplied packets automatically through the tunnel receive, bridge forward, and re-encapsulation path.\nS:U - The out-of-bounds read and resulting kernel oops occur within the kernel network stack on the same host; there is no crossing of a VM, container, or IOMMU security boundary beyond standard kernel memory safety failure.\nC:H - Reading through `icmp_hdr(skb)` when `transport_header` is unset causes an out-of-bounds read at `skb->head + 65535`, potentially disclosing adjacent kernel memory beyond the skb buffer before any bounds checking occurs.\nI:N - The flaw is an out-of-bounds read of the ICMP type field; it does not directly modify or write kernel memory, though it may cause a kernel fault.\nA:H - The invalid pointer dereference at offset 65535 can trigger a kernel oops or panic when accessing unmapped memory, causing denial of service on the affected host."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", 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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/ipv4/ip_tunnel_core.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "5a92cb45e34749865d03daf8d3500f77b5f6644c", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}, {"lessThan": "c7b7ec3e69e673c0d6b57f74d21da50c485c598e", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}, {"lessThan": "7f4f7efe7f30edd29c4988de01728bf2398217e4", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}, {"lessThan": "e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}, {"lessThan": "a096b6e34f602950af9a2b0856cd93a5f4c276d7", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}, {"lessThan": "43368636c663cff6e59dde93cf4b8e43ac28eb93", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}, {"lessThan": "cb549df9ce4ee15c9d5b19ddab12cf2128e4313c", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}, {"lessThan": "509323077ef79a26ba0c60bb556e45c12c398b2d", "status": "affected", "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/ipv4/ip_tunnel_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\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."}], "id": "CVE-2026-63992", "lastModified": "2026-07-30T14:51:11.223", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-19T16:17:38.700", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

{"bugzilla": {"description": "kernel: tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()", "id": "2502431", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502431"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-805", "details": ["In the Linux kernel, the following vulnerability has been resolved:\ntunnels: do not assume transport header in iptunnel_pmtud_check_icmp()\nIn some cases, iptunnel_pmtud_check_icmp() can be called while\nskb transport header is not set.\nThis triggers an out-of-bound access, because\n(typeof(skb->transport_header))~0U is 65535.\nAccess the icmp header based on IPv4 network header,\nafter making sure icmp->type is present in skb linear part.\nNote that iptunnel_pmtud_check_icmpv6()) is fine.", "A flaw was found in the Linux kernel's `tunnels` module. This vulnerability occurs when the `iptunnel_pmtud_check_icmp()` function is called without the `skb transport header` being properly set. An attacker could exploit this condition to trigger an out-of-bound memory access, which may lead to system instability or a denial of service."], "name": "CVE-2026-63992", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Not affected", "impact": "important", "package_name": "erlang27", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63992\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63992\nhttps://lore.kernel.org/linux-cve-announce/2026071904-CVE-2026-63992-2846@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,5a92cb45e34749865d03daf8d3500f77b5f6644c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,c7b7ec3e69e673c0d6b57f74d21da50c485c598e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,7f4f7efe7f30edd29c4988de01728bf2398217e4)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,a096b6e34f602950af9a2b0856cd93a5f4c276d7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,43368636c663cff6e59dde93cf4b8e43ac28eb93)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,cb549df9ce4ee15c9d5b19ddab12cf2128e4313c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4cb47a8644cc9eb8ec81190a50e79e6530d0297f,509323077ef79a26ba0c60bb556e45c12c398b2d)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "5.9"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,5.9)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.10.259,5.11.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.210,5.16.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.176,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.143,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.93,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.35,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.12,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-21T06:45:02.910187+00:00", "updated": "2026-08-04T06:30:05.486041+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}