{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64114", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.035Z", "datePublished": "2026-07-19T15:40:14.854Z", "dateUpdated": "2026-08-05T12:39:23.263Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:39:23.263Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: raw: reject IP_HDRINCL packets with ihl < 5\n\nraw_send_hdrinc() validates that the caller-supplied IPv4 header\nfits within the message length:\n\n iphlen = iph->ihl * 4;\n err = -EINVAL;\n if (iphlen > length)\n goto error_free;\n\n if (iphlen >= sizeof(*iph)) {\n /* fix up saddr, tot_len, id, csum, transport_header */\n }\n\nIt does not, however, reject ihl < 5. For such a packet the\n\"if (iphlen >= sizeof(*iph))\" branch is skipped, leaving the\ncrafted iphdr untouched, but the packet is still handed to\n__ip_local_out() and onward. Downstream consumers that read\niph->ihl assume a sane value: net/ipv4/ah4.c:ah_output() in\nparticular subtracts sizeof(struct iphdr) from top_iph->ihl * 4\nand passes the (signed-int-negative, then cast to size_t)\nresult to memcpy(), producing an OOB access of length close to\nSIZE_MAX and a host kernel panic.\n\nAn IPv4 header with ihl < 5 is malformed by definition (RFC 791:\n\"Internet Header Length is the length of the internet header in\n32 bit words ... Note that the minimum value for a correct header\nis 5.\"). The kernel should not be willing to inject such a\npacket into its own output path.\n\nReject \"iphlen < sizeof(*iph)\" alongside the existing\n\"iphlen > length\" check. This matches the principle that locally\nconstructed packets that re-enter the IP stack must pass the same\nbasic sanity tests that a foreign packet would be subjected to.\n\nOnce this lands, the \"if (iphlen >= sizeof(*iph))\" wrapper around\nthe fixup branch becomes redundant; left in place to keep the\npatch minimal and backport-friendly. A follow-up can unwrap it.\n\nNote that commit 86f4c90a1c5c (\"ipv4, ipv6: ensure raw socket\nmessage is big enough to hold an IP header\") ensures the message\nbuffer is large enough to hold an iphdr, but does not constrain\nthe self-reported iph->ihl.\n\nReachability: the malformed packet source is any caller with\nCAP_NET_RAW, including an unprivileged process in a user+net\nnamespace on a kernel with CONFIG_USER_NS=y. The reproduced AH\ncrash also requires a matching xfrm AH policy on the outgoing\nroute; a container granted CAP_NET_ADMIN can install that state\nand policy in its netns. Loopback bypasses xfrm_output, so the\ntrigger uses a real netdev.\n\nReproduced on UML + KASAN: kernel-mode fault at addr 0x0 with\nmemcpy_orig at the crash site. Same shape reproduces inside a\nrootless Docker container with --cap-add NET_ADMIN on a stock\ndistro kernel." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires local syscalls (socket/sendmsg on a raw IP_HDRINCL socket); malformed packets are injected locally into the output path, not via remote network ingress which validates ihl >= 5.\nAC:L - The attacker fully controls the crafted header ihl value and can install the required xfrm AH policy and route via CAP_NET_ADMIN in their own network namespace, making exploitation reliable without conditions outside attacker control.\nPR:L - Triggering requires CAP_NET_RAW for raw sockets and CAP_NET_ADMIN to install xfrm AH policy, both obtainable by an unprivileged user via user+network namespaces or a container granted NET_ADMIN without init-namespace root.\nUI:N - No victim interaction is required; the attacker sends the malformed packet directly through their own raw socket and configured IPsec policy.\nS:U - Impact is kernel memory corruption and panic within the same kernel security boundary; this is not a VM escape, sandbox escape, or cross-authority boundary violation.\nC:H - The integer underflow in ah_output() memcpy length produces an out-of-bounds read of near SIZE_MAX bytes, providing an arbitrary kernel memory read primitive beyond any bounded disclosure.\nI:H - The same memcpy with underflowed length causes a massive out-of-bounds write that can corrupt adjacent kernel heap memory and be leveraged for control-flow hijacking.\nA:H - The OOB memcpy reliably causes a kernel-mode fault and host panic, as reproduced with KASAN and in a rootless Docker container, denying all system availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/raw.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "1065b9efa4126df559b03a849c139ecfae92cd25", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "bc20dbd48c26e743f7e0845020c11ed2ce8b15ee", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "5a564f737ec54d63e8ee221d3ff396d07586d464", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "3c5411fa4944ed99af3d9d1de750ea8169b6dac9", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "145e9afa5b905229b4788bb72c3255f5a5f77508", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "7725cd3b471740fd23d25ed1da722c671fb2a5d3", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "bbe0be67de296176e7243c76e3d9f02f6ae9ff0b", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "915fab69823a14c170dbaa3b41978768e0fe62fc", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/raw.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.142", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.34", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.11", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.10.258" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.15.209" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.142" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.92" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.34" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.0.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/1065b9efa4126df559b03a849c139ecfae92cd25" }, { "url": "https://git.kernel.org/stable/c/bc20dbd48c26e743f7e0845020c11ed2ce8b15ee" }, { "url": "https://git.kernel.org/stable/c/5a564f737ec54d63e8ee221d3ff396d07586d464" }, { "url": "https://git.kernel.org/stable/c/3c5411fa4944ed99af3d9d1de750ea8169b6dac9" }, { "url": "https://git.kernel.org/stable/c/145e9afa5b905229b4788bb72c3255f5a5f77508" }, { "url": "https://git.kernel.org/stable/c/7725cd3b471740fd23d25ed1da722c671fb2a5d3" }, { "url": "https://git.kernel.org/stable/c/bbe0be67de296176e7243c76e3d9f02f6ae9ff0b" }, { "url": "https://git.kernel.org/stable/c/915fab69823a14c170dbaa3b41978768e0fe62fc" } ], "title": "ipv4: raw: reject IP_HDRINCL packets with ihl < 5", "x_generator": { "engine": "bippy-1.2.0" } } } }