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vuln-cve/data/2026/93xxx/CVE-2026-93138.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-93138",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-09-17T16:02:15.088Z",
"datePublished": "2026-09-17T16:11:38.795Z",
"dateUpdated": "2026-10-19T09:06:11.046Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-10-19T09:06:11.046Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix vmlinux BTF prep race in bpf_get_btf_vmlinux\n\nbpf_get_btf_vmlinux() lazily parses the vmlinux BTF under the\nbpf_verifier_lock, but publishes the result through a plain store\nand re-checks it through a plain lockless load. Nothing orders\nthe stores initializing the struct btf inside btf_parse_vmlinux()\nagainst the store publishing the pointer: On a weakly ordered\narch, a concurrent first-time caller taking the lockless fast\npath could in principle observe the pointer before the parsed\ncontents are visible. The mutex_unlock() does not help such a\nreader given it only synchronizes with a later acquisition of the\nsame lock. Thus, publish the pointer with smp_store_release()\nand read it on the fast path with smp_load_acquire().\n\nAcquire semantics are needed rather than a dependency-ordered\nREAD_ONCE(): btf_parse_vmlinux() also populates globals outside\nthe returned object (e.g. bpf_ctx_convert.t). An address\ndependency would only order accesses performed through the\npointer and not cover other globals."
}
],
"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 race is reached from local bpf(2) BPF_PROG_LOAD: bpf_prog_load() calls bpf_get_btf_vmlinux() on the attach_btf_id path, and bpf_check() always calls it before verification. No remote protocol message carries the data that publishes btf_vmlinux.\nAC:L - The attacker issues concurrent BPF_PROG_LOAD (or BPF_MAP_CREATE of BPF_MAP_TYPE_STRUCT_OPS into bpf_struct_ops_map_alloc) so one thread runs btf_parse_vmlinux() under bpf_verifier_lock while the other takes the lockless `if (!btf_vmlinux)` load; they control both sides of that publication window.\nPR:L - The lockless consumer is bpf_check() when bpf_token_capable(token, CAP_BPF) sets is_priv and skips mutex_lock(&bpf_verifier_lock). CAP_BPF is delegable with a BPF token into a non-init user namespace, so init-namespace root is not required.\nUI:N - The attacker issues the concurrent bpf(BPF_PROG_LOAD) or bpf(BPF_MAP_CREATE) syscalls themselves; no other user must mount a filesystem, open a file, or load a program.\nS:U - A torn struct btf and bpf_ctx_convert.t are consumed by the host verifier and BTF helpers in the same kernel; that is in-kernel privilege escalation or DoS, not a KVM/Xen guest-to-host escape or IOMMU bypass.\nC:H - A lockless reader can observe btf_vmlinux before btf->types, btf->strings and btf->hdr.str_len are visible. btf_type_by_id() then returns btf->types[id] and btf_str_by_offset() returns &btf->strings[offset] (check_ptr_to_map_access, btf_find_by_name_kind), an unbounded kernel read.\nI:H - Privileged bpf_check() trusts that torn vmlinux BTF for PTR_TO_BTF_ID sizes, and get_kern_ctx_btf_id() walks bpf_ctx_convert.t members; garbage type metadata can accept illegal kernel stores. btf_get/btf_put on a not-yet-visible refcnt can also call_rcu btf_free_rcu of the live object.\nA:H - get_kern_ctx_btf_id() does btf_type_member(bpf_ctx_convert.t) with no NULL check when that global is still unseen, and check_ptr_to_map_access() loads t->name_off after btf_type_by_id() returns NULL because nr_types is still 0, oopsing the kernel."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/bpf/verifier.c"
],
"versions": [
{
"version": "8580ac9404f6240668a026785d7d8856f0530409",
"lessThan": "f32a4a40bc635be25d6816da4bd91e9e58c31bf3",
"status": "affected",
"versionType": "git"
},
{
"version": "8580ac9404f6240668a026785d7d8856f0530409",
"lessThan": "a7fe72d780122eb934536f1719abad445f6afdf7",
"status": "affected",
"versionType": "git"
},
{
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"lessThan": "e18a10b39c994f04e1ebd7f8fc042bb1ca8ad053",
"status": "affected",
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"lessThan": "86d11c594d60b255b526fa5260f669463fb1a063",
"status": "affected",
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{
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{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/bpf/verifier.c"
],
"versions": [
{
"version": "5.5",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.5",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.10.270",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.15.221",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
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},
{
"version": "6.1.188",
"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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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"references": [
{
"url": "https://git.kernel.org/stable/c/f32a4a40bc635be25d6816da4bd91e9e58c31bf3"
},
{
"url": "https://git.kernel.org/stable/c/a7fe72d780122eb934536f1719abad445f6afdf7"
},
{
"url": "https://git.kernel.org/stable/c/e18a10b39c994f04e1ebd7f8fc042bb1ca8ad053"
},
{
"url": "https://git.kernel.org/stable/c/978524ecfc1c539282df5858de1eec20748c6f74"
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{
"url": "https://git.kernel.org/stable/c/eaf302628a78806f66d8224d6ba03fb4d5025de4"
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},
{
"url": "https://git.kernel.org/stable/c/92863e678070f57c17c868e4bfa2441a5c61ad2b"
}
],
"title": "bpf: Fix vmlinux BTF prep race in bpf_get_btf_vmlinux",
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