CVE-2026-93111 (GCVE-0-2026-93111)
Vulnerability from cvelistv5
Published
2026-09-17 16:11
Modified
2026-10-19 09:05
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Mark tracing_multi trampolines as ftrace managed
Since tracing_multi link does not set ftrace_managed, it would fail to
release the tracing_multi link when attaching tracing_multi link and
then attaching fentry link.
[ 3.714215] WARNING: kernel/bpf/trampoline.c:1727 at bpf_trampoline_multi_detach+0x20b/0x240, CPU#1: test_progs/97
...
[ 3.733170] bpf_tracing_multi_link_release+0x14/0x30
[ 3.733890] bpf_link_free+0x58/0x130
[ 3.734414] bpf_link_release+0x23/0x30
Fix it by setting 'ftrace_managed = true' in register_fentry_multi().
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/bpf/trampoline.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "280145253fd38fa975cc04963ddaf74c7f415011",
"status": "affected",
"version": "aef4dfa790b22d8052cfb78044eadbe03c876c39",
"versionType": "git"
},
{
"lessThan": "30bdd6d1384d894931f113eb595636092d8e650c",
"status": "affected",
"version": "aef4dfa790b22d8052cfb78044eadbe03c876c39",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/bpf/trampoline.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.2"
},
{
"lessThan": "7.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.6",
"versionStartIncluding": "7.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "7.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"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 \u0027ftrace_managed = true\u0027 in register_fentry_multi()."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Reached only via local bpf(2): BPF_PROG_LOAD of BPF_TRACE_FENTRY_MULTI then BPF_LINK_CREATE \u2192 link_create() \u2192 bpf_tracing_multi_attach() \u2192 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-\u003efunc.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 \u2192 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\u2019s 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\u2019s recorded direct target no longer matches the poked site, and the subsequent jump into the freed bpf_tramp_image oopses or panics."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T09:05:44.850Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/280145253fd38fa975cc04963ddaf74c7f415011"
},
{
"url": "https://git.kernel.org/stable/c/30bdd6d1384d894931f113eb595636092d8e650c"
}
],
"title": "bpf: Mark tracing_multi trampolines as ftrace managed",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-93111",
"datePublished": "2026-09-17T16:11:20.464Z",
"dateReserved": "2026-09-17T16:02:15.086Z",
"dateUpdated": "2026-10-19T09:05:44.850Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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