256 lines
15 KiB
JSON
256 lines
15 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-72444",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-08-09T03:40:39.930Z",
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"datePublished": "2026-08-15T05:56:55.229Z",
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"dateUpdated": "2026-10-16T18:55:24.524Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-08-17T05:44:16.441Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nflow_dissector: check device type before reading ETH_ADDRS\n\n__skb_flow_dissect() unconditionally reads 12 bytes from eth_hdr(skb)\nwhen FLOW_DISSECTOR_KEY_ETH_ADDRS is requested. This assumes the skb\nhas a valid Ethernet header at mac_header, which is not always the case.\n\nThe problem can be triggered by:\n 1. Creating a TUN device in L3 mode (IFF_TUN, hard_header_len=0)\n 2. Attaching a multiq qdisc with a flower filter matching on eth_src\n 3. Sending a packet through AF_PACKET\n\nSince TUN in L3 mode has no link-layer header, mac_header points to\nthe L3 data area. The flow dissector reads 12 bytes of uninitialized\nskb memory, which then propagates through fl_set_masked_key() and is\nused as a rhashtable lookup key in __fl_lookup(), as reported by KMSAN.\n\nRejecting the filter in the control path (at tc filter add time) is\nnot feasible because TC filter blocks can be shared between arbitrary\ndevices -- a filter installed on an Ethernet device may later classify\npackets on a headerless device through a shared block. The device\nassociation is not fixed at filter creation time.\n\nFix this by gating the memcpy on dev->type == ARPHRD_ETHER, which\nensures only true Ethernet-framed packets have their addresses read.\nThis is more precise than the previous hard_header_len >= 12 check,\nwhich would incorrectly pass for non-Ethernet link types like IPoIB\n(ARPHRD_INFINIBAND, hard_header_len=24) and FDDI (hard_header_len=21)\nwhose L2 headers are not in Ethernet format. Additionally check\nskb_mac_header_was_set() to guard against the pathological case where\nmac_header is the unset sentinel (~0U), which would cause eth_hdr() to\nreturn a wild pointer.\n\nFor the act_mirred redirect case (Ethernet packet redirected to a\nnon-Ethernet device sharing a TC block), zeroing the key is the correct\nbehavior: the packet is now being classified on the target device, where\nEthernet address matching is not semantically meaningful.\n\nNote: on non-Ethernet devices, the zeroed key will match a filter\nconfigured with all-zero MAC addresses. This is an improvement over the\nprevious behavior where uninitialized memory could randomly match any\nfilter."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The bug is hit from TC flower classification (fl_classify) on packets injected locally via AF_PACKET through an L3 TUN with mq/flower qdisc; per kernel guidance TC/netlink qdisc paths are Local, not remotely reachable network stack handlers.\nAC:L - Syzbot and the fix commit show reliable reproduction by creating an L3 TUN, attaching a multiq qdisc with a flower eth_src filter, and sending packets via AF_PACKET; the attacker controls every setup step with no races or rare kernel config.\nPR:L - Exploitation requires CAP_NET_ADMIN to create/configure the TUN and install TC flower filters via rtnetlink, plus CAP_NET_RAW for AF_PACKET sockets; both capabilities are obtainable by an unprivileged user inside a user+network namespace (unshare -Urn).\nUI:N - No victim user action is required; exploitation uses attacker-controlled local syscalls (TUN ioctl, rtnetlink TC setup, AF_PACKET sendmsg) in a namespace they create.\nS:U - Impact stays within the kernel networking/TC subsystem of the host or attacker-controlled namespace; it does not cross VM, sandbox, or IOMMU security boundaries.\nC:H - __skb_flow_dissect copies 12 bytes from eth_hdr(skb) when FLOW_DISSECTOR_KEY_ETH_ADDRS is set; on headerless devices (L3 TUN, ARPHRD_NONE) mac_header points at L3 data or unset headroom, leaking uninitialized or out-of-bounds kernel memory into flow keys used by __fl_lookup.\nI:H - Garbage eth address keys flow through fl_set_masked_key into rhashtable lookup and can spuriously match flower filters, invoking unintended TC actions (police drop, skb mark, act_mirred redirect) that alter packet handling beyond the attacker's own data.\nA:H - When mac_header is the unset sentinel (~0U), eth_hdr() becomes a wild pointer and the memcpy can page-fault with a kernel oops/panic; even without fault, mis-matched filters can apply drop/redirect actions that deny or disrupt packet delivery."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"net/core/flow_dissector.c"
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],
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"versions": [
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{
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"version": "67a900cc0436d74e7ff89042371760def087680d",
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"lessThan": "0fe6455b8e1a22414f39c07bc90a1df12b52ec74",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "67a900cc0436d74e7ff89042371760def087680d",
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"lessThan": "9a65860959db594dfc1820c7fdc09285fb7556bf",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "67a900cc0436d74e7ff89042371760def087680d",
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"lessThan": "594c90b197141944f25991b8314de5c26ee27a7e",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "67a900cc0436d74e7ff89042371760def087680d",
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"lessThan": "c6d3bcb0f934d4297ac5fa1c8656ae40694fb601",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "67a900cc0436d74e7ff89042371760def087680d",
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"lessThan": "825de39f0c35a112148799b3cbe45af3766c018a",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "67a900cc0436d74e7ff89042371760def087680d",
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"lessThan": "bf6e8af2c8be77489bedeae9f8a9654cb710e500",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"net/core/flow_dissector.c"
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],
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"versions": [
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{
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"version": "4.2",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "4.2",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.1.178",
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"lessThanOrEqual": "6.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.6.145",
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"lessThanOrEqual": "6.6.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12.97",
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"lessThanOrEqual": "6.12.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.40",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.1.5",
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"lessThanOrEqual": "7.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.2",
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"versionEndExcluding": "6.1.178"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.2",
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"versionEndExcluding": "6.6.145"
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{
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.2",
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.2",
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"versionEndExcluding": "7.2"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/0fe6455b8e1a22414f39c07bc90a1df12b52ec74"
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},
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{
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"url": "https://git.kernel.org/stable/c/9a65860959db594dfc1820c7fdc09285fb7556bf"
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},
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{
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"url": "https://git.kernel.org/stable/c/594c90b197141944f25991b8314de5c26ee27a7e"
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},
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{
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"url": "https://git.kernel.org/stable/c/c6d3bcb0f934d4297ac5fa1c8656ae40694fb601"
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},
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{
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"url": "https://git.kernel.org/stable/c/825de39f0c35a112148799b3cbe45af3766c018a"
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},
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{
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"url": "https://git.kernel.org/stable/c/bf6e8af2c8be77489bedeae9f8a9654cb710e500"
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}
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],
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"title": "flow_dissector: check device type before reading ETH_ADDRS",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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},
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"id": "CVE-2026-72444",
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"role": "CISA Coordinator",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "total"
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}
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],
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"version": "2.0.3",
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"timestamp": "2026-10-16T18:50:08.470597Z"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-10-16T18:55:24.524Z"
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}
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}
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]
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}
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} |