CVE-2026-72111 (GCVE-0-2026-72111)
Vulnerability from cvelistv5
Published
2026-08-15 05:52
Modified
2026-08-17 05:40
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Reset register bounds before narrowing retval range in check_mem_access()
When the BPF verifier processes a context load of an LSM hook return
value, it calls __mark_reg_s32_range() to narrow the register to the
hook's valid range. However, __mark_reg_s32_range() intersects the new
range with the register's existing bounds using max_t()/min_t() rather
than replacing them.
If the destination register carries stale bounds from a prior instruction
(e.g. BPF_MOV64_IMM), the intersection can produce a range narrower than
reality. The verifier then believes it knows the register's exact value,
while at runtime the actual hook return value is loaded, creating a
verifier/runtime mismatch that can be used to bypass BPF memory safety
checks.
The else branch already calls mark_reg_unknown() to reset register state
before any narrowing. Apply the same reset in the is_retval path so
stale bounds are cleared before __mark_reg_s32_range() intersects.
References
| URL | Tags | |
|---|---|---|
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 Version: 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 Version: 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 Version: 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 Version: 1050727d83e70449991c29dd1cf29fe936a63da3 Version: 27ca3e20fe80be85a92b10064dfeb56cb2564b1c Version: 6.10.13 ≤ Version: 6.11.2 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/bpf/verifier.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "5d99e198be279045e6ecefe220f5c52f8ce9bfd5",
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{
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},
{
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"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
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{
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"versionType": "git"
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{
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"version": "27ca3e20fe80be85a92b10064dfeb56cb2564b1c",
"versionType": "git"
},
{
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"status": "affected",
"version": "6.10.13",
"versionType": "semver"
},
{
"lessThan": "6.12",
"status": "affected",
"version": "6.11.2",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/bpf/verifier.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.12"
},
{
"lessThan": "6.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.103",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.40",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.10.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.11.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reset register bounds before narrowing retval range in check_mem_access()\n\nWhen the BPF verifier processes a context load of an LSM hook return\nvalue, it calls __mark_reg_s32_range() to narrow the register to the\nhook\u0027s valid range. However, __mark_reg_s32_range() intersects the new\nrange with the register\u0027s existing bounds using max_t()/min_t() rather\nthan replacing them.\n\nIf the destination register carries stale bounds from a prior instruction\n(e.g. BPF_MOV64_IMM), the intersection can produce a range narrower than\nreality. The verifier then believes it knows the register\u0027s exact value,\nwhile at runtime the actual hook return value is loaded, creating a\nverifier/runtime mismatch that can be used to bypass BPF memory safety\nchecks.\n\nThe else branch already calls mark_reg_unknown() to reset register state\nbefore any narrowing. Apply the same reset in the is_retval path so\nstale bounds are cleared before __mark_reg_s32_range() intersects."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The flaw is reached only through bpf(BPF_PROG_LOAD) during bpf_check()-\u003echeck_mem_access() when a BPF_LSM_MAC program loads the LSM hook return value from PTR_TO_CTX; per kernel CNA guidance BPF verifier issues are Local even if attached programs later run on file, socket, or network LSM hooks.\nAC:L - An attacker fully controls the BPF instruction sequence (e.g., BPF_MOV64_IMM to leave stale bounds, then a ctx retval load) and can deterministically force __mark_reg_s32_range() to intersect into an overly narrow range without races, special memory layout, or other uncontrollable conditions.\nPR:L - Loading BPF_PROG_TYPE_LSM programs requires CAP_BPF and CAP_PERFMON (is_perfmon_prog_type), both blocked for unprivileged users when kernel.unprivileged_bpf_disabled is set but obtainable inside user namespaces on typical CONFIG_BPF_LSM systems per kernel CNA BPF guidance.\nUI:N - No victim interaction is required; the attacker loads, verifies, and attaches their own malicious BPF LSM program and triggers the attached LSM hook with their own local syscalls or network operations.\nS:C - A container or user-namespace tenant with namespace-granted CAP_BPF can load a verifier-bypassing BPF LSM program whose runtime memory corruption executes in host kernel context on LSM hook firing, crossing the container-to-host security boundary on multi-tenant cloud and Android-style deployments.\nC:H - The verifier/runtime register-bounds mismatch lets unsafe BPF programs pass verification and perform out-of-bounds reads on ctx, stack, or map memory at runtime, a memory-corruption primitive that can be developed into arbitrary kernel memory disclosure.\nI:H - False exact-knowledge of the LSM return-value register enables verifier-approved pointer arithmetic and memory writes that are invalid at runtime, enabling out-of-bounds writes and control-flow hijacking toward arbitrary kernel code execution from BPF context.\nA:H - Running verifier-incorrect BPF LSM programs can trigger kernel oops or panic from corrupted memory accesses, and once attached the attacker can repeatedly invoke the hook to cause repeatable host-wide denial of service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:40:25.647Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/bde92f65042ec14389782dd223f706bf6b59ce5d"
},
{
"url": "https://git.kernel.org/stable/c/0993dc5fc619c0b25ab1310cb11d65e78351c0fe"
},
{
"url": "https://git.kernel.org/stable/c/5a55f9aecc08990940e70f0c7048a80850c5a16a"
},
{
"url": "https://git.kernel.org/stable/c/5e0b273e0a62cc04ec338c7b502797c66c2ed42a"
}
],
"title": "bpf: Reset register bounds before narrowing retval range in check_mem_access()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72111",
"datePublished": "2026-08-15T05:52:52.538Z",
"dateReserved": "2026-08-09T03:40:39.906Z",
"dateUpdated": "2026-08-17T05:40:25.647Z",
"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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