256 lines
14 KiB
JSON
256 lines
14 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-2026-74544",
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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": "2026-08-15T05:44:03.914Z",
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"datePublished": "2026-08-15T12:27:53.941Z",
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"dateUpdated": "2026-10-30T12:30:09.940Z"
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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": "2026-10-30T12:30:09.940Z"
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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\nnet/sched: cls_u32: validate offshift to prevent shift-out-of-bounds\n\nu32_change() copies the user-provided tc_u32_sel.offshift (unsigned char,\n0-255) into the kernel knode object without bounds validation. When a\npacket later hits u32_classify() with TC_U32_VAROFFSET set, it evaluates\n`ntohs(offmask & *data) >> offshift` where the left operand is a 16-bit\nvalue promoted to a 32-bit int. Any offshift >= 32 is undefined behavior\nper C11 6.5.7p3, triggerable by an unprivileged user via user/network\nnamespaces.\n\nUBSAN: shift-out-of-bounds in net/sched/cls_u32.c:236:43\nshift exponent 32 is too large for 32-bit type int\n\nFix this by rejecting offshift >= 16 during filter creation in\nu32_change()."
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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 configured through RTM_NEWTFILTER rtnetlink (tc filter add) in u32_change(); per kernel CNA guidance, tc/qdisc/netlink classifier setup is Local even though subsequent packets invoke u32_classify() on ingress/egress paths.\nAC:L - The attacker fully controls offshift (32-255), TC_U32_VAROFFSET selector flags, and matching packet bytes when installing the filter and sending traffic through the attached qdisc; no race or external victim state is required.\nPR:L - Creating u32 filters requires CAP_NET_ADMIN, which an unprivileged local user obtains in a user/network namespace via unshare -Urn; rtnetlink enforces netlink_net_capable() against that namespace's user_ns, not only init-root.\nUI:N - The attacker installs the malicious u32 filter and injects triggering packets themselves within their namespace; no separate victim action (opening files, mounting media, clicking links) is needed.\nS:U - Corrupted classifier offset arithmetic and any resulting kernel crash stay within the host kernel's security authority; this is standard local kernel compromise, not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - Undefined-behavior right-shift (offshift>=32) on packet-derived values corrupts variable offset math in u32_classify(), driving attacker-influenced skb_header_pointer reads at unintended offsets; per CNA guidance, exploitable kernel memory-unsafe operations warrant High confidentiality impact.\nI:H - Invalid shift results corrupt off2 and unsigned off accumulation in the classifier hot path, derailing cls_u32 control flow; C11 undefined behavior in kernel packet classification is exploitable for integrity compromise and potential code execution per CNA memory-corruption guidance.\nA:H - Hitting u32_classify() with offshift>=32 provokes documented UBSAN shift-out-of-bounds at cls_u32.c:236; undefined shifts can also trigger kernel oops/panic during packet classification, satisfying CNA guidance that kernel crashes are High availability impact."
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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/sched/cls_u32.c"
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],
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"versions": [
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{
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"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
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"lessThan": "7fd5b2287e5cf33e114fb7f0cef781a546039757",
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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": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
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"lessThan": "724c8edbacf1259988829cb9967f751222121d8a",
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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": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
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"lessThan": "006a4598da9a6b02e0ddc3ca5042b97224774364",
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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": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
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"lessThan": "9990cac513e8b191de2ee589051ea7ebf3cee940",
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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": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
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"lessThan": "313cb9ffc4101a885d791facf4b5ea3d5e06144d",
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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": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
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"lessThan": "aef96eead2860cbfa371e4471d4f04412213b958",
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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/sched/cls_u32.c"
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],
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"versions": [
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{
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"version": "2.6.12",
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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": "2.6.12",
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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": "6.1.191",
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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": "6.6.160",
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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": "6.12.114",
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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": "6.18.57",
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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": "7.1.8",
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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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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "2.6.12",
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"versionEndExcluding": "6.1.191"
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"vulnerable": true,
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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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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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/7fd5b2287e5cf33e114fb7f0cef781a546039757"
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},
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{
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"url": "https://git.kernel.org/stable/c/724c8edbacf1259988829cb9967f751222121d8a"
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},
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{
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"url": "https://git.kernel.org/stable/c/006a4598da9a6b02e0ddc3ca5042b97224774364"
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},
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{
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"url": "https://git.kernel.org/stable/c/9990cac513e8b191de2ee589051ea7ebf3cee940"
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},
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{
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"url": "https://git.kernel.org/stable/c/313cb9ffc4101a885d791facf4b5ea3d5e06144d"
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},
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{
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"url": "https://git.kernel.org/stable/c/aef96eead2860cbfa371e4471d4f04412213b958"
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}
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],
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"title": "net/sched: cls_u32: validate offshift to prevent shift-out-of-bounds",
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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-2026-74544",
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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": "2026-10-16T18:59:49.230429Z"
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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": "2026-10-16T19:05:54.903Z"
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}
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}
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]
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}
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} |