138 lines
8.1 KiB
JSON
138 lines
8.1 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-2026-93111",
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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": "2026-09-17T16:02:15.086Z",
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"datePublished": "2026-09-17T16:11:20.464Z",
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"dateUpdated": "2026-10-19T09:05:44.850Z"
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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": "2026-10-19T09:05:44.850Z"
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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\nbpf: Mark tracing_multi trampolines as ftrace managed\n\nSince tracing_multi link does not set ftrace_managed, it would fail to\nrelease the tracing_multi link when attaching tracing_multi link and\nthen attaching fentry link.\n\n[ 3.714215] WARNING: kernel/bpf/trampoline.c:1727 at bpf_trampoline_multi_detach+0x20b/0x240, CPU#1: test_progs/97\n...\n[ 3.733170] bpf_tracing_multi_link_release+0x14/0x30\n[ 3.733890] bpf_link_free+0x58/0x130\n[ 3.734414] bpf_link_release+0x23/0x30\n\nFix it by setting 'ftrace_managed = true' in register_fentry_multi()."
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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 - Reached only via local bpf(2): BPF_PROG_LOAD of BPF_TRACE_FENTRY_MULTI then BPF_LINK_CREATE → link_create() → bpf_tracing_multi_attach() → register_fentry_multi(), then a regular BPF_TRACE_FENTRY BPF_LINK_CREATE through bpf_tracing_prog_attach(). The trigger is that attach order, not a remote protocol message.\nAC:L - The attacker chooses the order: tracing_multi first so register_fentry_multi() never sets tr->func.ftrace_managed, then fentry so modify_fentry() takes bpf_arch_text_poke() instead of direct_ops_mod(), then close() of the tracing_multi fd into bpf_trampoline_multi_detach(). No race or uninfluenced victim state is required.\nPR:L - bpf_prog_load() for BPF_PROG_TYPE_TRACING (fentry.multi and fentry) requires bpf_token_capable(CAP_BPF) and, via is_perfmon_prog_type(), bpf_token_capable(CAP_PERFMON). Those caps are delegable with a BPF token into a non-init user namespace, so this is Low rather than init-namespace root.\nUI:N - The attacker loads both programs, creates the tracing_multi and fentry links, and closes the tracing_multi fd themselves (bpf_link_release → bpf_tracing_multi_link_release). No other user must mount, open, or otherwise act on attacker-supplied objects.\nS:U - The use-after-free is of a kernel bpf_tramp_image that remains an ftrace direct-call target. That is in-kernel privilege escalation, not a KVM/Xen guest-to-host or IOMMU boundary cross, so scope stays Unchanged.\nC:H - modify_fentry() text-pokes the fentry site to Image B and bpf_tramp_image_put()s Image A; bpf_trampoline_multi_detach() still bpf_tramp_image_put()s Image B in bpf_trampoline_multi_attach_free() after update_ftrace_direct_del/mod fails, so a later call of the hooked function executes freed trampoline memory.\nI:H - The hooked function’s live CALL/JMP still targets the trampoline image bpf_trampoline_multi_attach_free() freed after the failed ftrace update, so reclaiming that JIT page hijacks control flow at the ftrace site (arbitrary kernel write/execute).\nA:H - bpf_trampoline_multi_detach() hits WARN_ON_ONCE(update_ftrace_direct_del()) at trampoline.c:1727 when ftrace’s recorded direct target no longer matches the poked site, and the subsequent jump into the freed bpf_tramp_image oopses or panics."
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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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"kernel/bpf/trampoline.c"
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],
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"versions": [
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{
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"version": "aef4dfa790b22d8052cfb78044eadbe03c876c39",
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"lessThan": "280145253fd38fa975cc04963ddaf74c7f415011",
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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": "aef4dfa790b22d8052cfb78044eadbe03c876c39",
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"lessThan": "30bdd6d1384d894931f113eb595636092d8e650c",
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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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"kernel/bpf/trampoline.c"
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],
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"versions": [
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{
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"version": "7.2",
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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": "7.2",
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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": "7.2.6",
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"lessThanOrEqual": "7.2.*",
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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": "7.3",
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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": "7.2",
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"versionEndExcluding": "7.2.6"
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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": "7.2",
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"versionEndExcluding": "7.3"
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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/280145253fd38fa975cc04963ddaf74c7f415011"
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},
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{
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"url": "https://git.kernel.org/stable/c/30bdd6d1384d894931f113eb595636092d8e650c"
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}
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],
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"title": "bpf: Mark tracing_multi trampolines as ftrace managed",
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