{ "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" }, { "version": "8580ac9404f6240668a026785d7d8856f0530409", "lessThan": "e18a10b39c994f04e1ebd7f8fc042bb1ca8ad053", "status": "affected", "versionType": "git" }, { "version": "8580ac9404f6240668a026785d7d8856f0530409", "lessThan": "978524ecfc1c539282df5858de1eec20748c6f74", "status": "affected", "versionType": "git" }, { "version": "8580ac9404f6240668a026785d7d8856f0530409", "lessThan": "eaf302628a78806f66d8224d6ba03fb4d5025de4", "status": "affected", "versionType": "git" }, { "version": "8580ac9404f6240668a026785d7d8856f0530409", "lessThan": "2892f3f44bf865c8fb6b6c0960edec4cc91806ee", "status": "affected", "versionType": "git" }, { "version": "8580ac9404f6240668a026785d7d8856f0530409", "lessThan": "86d11c594d60b255b526fa5260f669463fb1a063", "status": "affected", "versionType": "git" }, { "version": "8580ac9404f6240668a026785d7d8856f0530409", "lessThan": "92863e678070f57c17c868e4bfa2441a5c61ad2b", "status": "affected", "versionType": "git" } ] }, { "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", "versionType": "semver" }, { "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" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.18.52" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.3" } ] } ] } ], "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" }, { "url": "https://git.kernel.org/stable/c/eaf302628a78806f66d8224d6ba03fb4d5025de4" }, { "url": "https://git.kernel.org/stable/c/2892f3f44bf865c8fb6b6c0960edec4cc91806ee" }, { "url": "https://git.kernel.org/stable/c/86d11c594d60b255b526fa5260f669463fb1a063" }, { "url": "https://git.kernel.org/stable/c/92863e678070f57c17c868e4bfa2441a5c61ad2b" } ], "title": "bpf: Fix vmlinux BTF prep race in bpf_get_btf_vmlinux", "x_generator": { "engine": "bippy-1.2.0" } } } }