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vuln-cve/data/2026/90xxx/CVE-2026-90392.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-90392",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-09-11T19:38:34.810Z",
"datePublished": "2026-09-17T16:09:25.738Z",
"dateUpdated": "2026-10-30T12:35:28.141Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-10-30T12:35:28.141Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix potential UAF when reading bpf link info\n\nIn bpf_link_show_fdinfo and bpf_link_get_info_by_fd, link->prog is\naccessed without holding any locks. If the prog is concurrently replaced\nvia bpf_link_update, the old prog can be freed, leading to a potential\nUAF issue.\n\nFix this by accessing link->prog under RCU protection to safely fetch\nthe pointer and guarantee its lifetime while reading its fields."
}
],
"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 - The dangling link->prog is read from the local bpf(2) BPF_OBJ_GET_INFO_BY_FD command (bpf_obj_get_info_by_fd()->bpf_link_get_info_by_fd()) or from bpf_link_show_fdinfo() when reading /proc/self/fdinfo on a bpf_link fd; neither path takes the malformed state from a network protocol.\nAC:L - The attacker owns both sides: one thread issues BPF_LINK_UPDATE so link_update() runs cgroup_bpf_replace()/tcx_link_update()/sock_map_link_update_prog() which xchg(&link->prog) and bpf_prog_put() the old program, while another thread they control races bpf_link_get_info_by_fd() or bpf_link_show_fdinfo(), which sleeps in seq_printf after capturing the pointer.\nPR:L - Creating a replaceable link requires bpf_prog_load() of a type whose ops implement update_prog (CGROUP_SKB, SCHED_CLS, SK_SKB, XDP, FLOW_DISSECTOR) plus BPF_LINK_CREATE; those paths require bpf_token_capable(CAP_BPF) and usually CAP_NET_ADMIN (CGROUP_SKB attach also checks it in bpf_prog_attach_check_attach_type), which a BPF token delegates into a user namespace.\nUI:N - The attacker loads two programs, BPF_LINK_CREATE the first as a cgroup/tcx/sockmap/xdp/netns link, closes the old program fd so the link holds the last ref, then races BPF_LINK_UPDATE against BPF_OBJ_GET_INFO_BY_FD or fdinfo in their own process; no other user action is required.\nS:U - The use-after-free is of the replaced bpf_prog inside bpf_link_get_info_by_fd()/bpf_link_show_fdinfo() on the host kernel; impact is local kernel memory corruption and privilege escalation, not a VM, IOMMU, or other authority-boundary cross.\nC:H - After the concurrent bpf_prog_put(), bpf_link_get_info_by_fd() reads prog->aux->id and bpf_link_show_fdinfo() copies prog->tag then aux->id from the freed bpf_prog; __bpf_prog_free() kfree()s the kmalloc bpf_prog_aux, so reclaiming that object turns the dangling aux pointer into an arbitrary kernel read.\nI:H - The same bpf_prog/bpf_prog_aux use-after-free after cgroup_bpf_replace() (or tcx/sockmap/xdp/netns update_prog) lets the attacker spray the freed kmalloc aux and vmalloc prog; kernel heap UAF of those objects yields write and control-flow hijack primitives.\nA:H - bpf_link_get_info_by_fd() and bpf_link_show_fdinfo() dereference the freed bpf_prog and prog->aux after BPF_LINK_UPDATE drops the last ref via bpf_prog_put(); a recycled or poisoned aux pointer causes a kernel oops."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/bpf/syscall.c"
],
"versions": [
{
"version": "0c991ebc8c69d29b7fc44db17075c5aa5253e2ab",
"lessThan": "4c8432a332d4a24dc2742f56062a53d8fad36f53",
"status": "affected",
"versionType": "git"
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{
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"status": "affected",
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"lessThan": "d7d7208e2603b45724b684f4df73904fb347741e",
"status": "affected",
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{
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"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/bpf/syscall.c"
],
"versions": [
{
"version": "5.7",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.7",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.1.191",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.6.157",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.12.110",
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.52",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.2.6",
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
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"cpeApplicability": [
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"nodes": [
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"operator": "OR",
"negate": false,
"cpeMatch": [
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"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"references": [
{
"url": "https://git.kernel.org/stable/c/4c8432a332d4a24dc2742f56062a53d8fad36f53"
},
{
"url": "https://git.kernel.org/stable/c/a5c936ac904767fc1d943d40b0308bcb2ae2509b"
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{
"url": "https://git.kernel.org/stable/c/d7d7208e2603b45724b684f4df73904fb347741e"
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"url": "https://git.kernel.org/stable/c/85cf991c881e7198be32be05a9daa2625390c8b3"
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"url": "https://git.kernel.org/stable/c/79347e42cfbc9e78872922e8f08a70609c9af82f"
},
{
"url": "https://git.kernel.org/stable/c/863f3ddd0b8ac65abfb50d3be0869268ac0e277b"
}
],
"title": "bpf: Fix potential UAF when reading bpf link info",
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}