CVE-2026-74470 (GCVE-0-2026-74470)
Vulnerability from cvelistv5
Published
2026-08-15 12:27
Modified
2026-08-23 12:47
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write
resp_report_zones() sizes the reply buffer from the CDB allocation
length. The v3 fix rounds alloc_len up with ALIGN() before deriving the
descriptor count:
rep_max_zones = (ALIGN((u64)alloc_len, RZONES_DESC_HD) -
RZONES_DESC_HD) >> ilog2(RZONES_DESC_HD);
arr_len = (u64)RZONES_DESC_HD * (rep_max_zones + 1);
For alloc_len in 0xFFFFFFC1..0xFFFFFFFF, ALIGN() rounds up to
0x100000000, so arr_len is 4 GB. On 32-bit, kzalloc()'s size_t is 32-bit
and truncates 0x100000000 to 0; kzalloc(0) returns ZERO_SIZE_PTR, which
passes the !arr check, and desc = arr + 64 is then dereferenced in the
loop -> out-of-bounds write / panic.
Clamp rep_max_zones to devip->nr_zones. The loop already stops at
sdebug_capacity (after nr_zones zones), so a report can never hold more
than nr_zones descriptors; the clamp does not change the report, it only
bounds arr_len to (nr_zones + 1) * RZONES_DESC_HD, a real device
property that can never reach 0x100000000.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: ebacb44cb2042b90951140eda806bedad23ef554 Version: 7db0e0c8190a086ef92ce5bb960836cde49540aa Version: 7db0e0c8190a086ef92ce5bb960836cde49540aa Version: 7db0e0c8190a086ef92ce5bb960836cde49540aa Version: 7db0e0c8190a086ef92ce5bb960836cde49540aa Version: 7db0e0c8190a086ef92ce5bb960836cde49540aa Version: 7db0e0c8190a086ef92ce5bb960836cde49540aa Version: c4d2d7c935a4ad20e8e726ca10499cefe4537103 Version: 5.15.8 ≤ Version: 5.10.85 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/scsi/scsi_debug.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "ebacb44cb2042b90951140eda806bedad23ef554",
"versionType": "git"
},
{
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"status": "affected",
"version": "7db0e0c8190a086ef92ce5bb960836cde49540aa",
"versionType": "git"
},
{
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"status": "affected",
"version": "7db0e0c8190a086ef92ce5bb960836cde49540aa",
"versionType": "git"
},
{
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{
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{
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"versionType": "git"
},
{
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"version": "c4d2d7c935a4ad20e8e726ca10499cefe4537103",
"versionType": "git"
},
{
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"status": "affected",
"version": "5.15.8",
"versionType": "semver"
},
{
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"status": "affected",
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]
},
{
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"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.16"
},
{
"lessThan": "5.16",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"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": "5.15.217",
"versionStartIncluding": "5.15.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.183",
"versionStartIncluding": "5.16",
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},
{
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{
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.44",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.8",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
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"versionStartIncluding": "5.10.85",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write\n\nresp_report_zones() sizes the reply buffer from the CDB allocation\nlength. The v3 fix rounds alloc_len up with ALIGN() before deriving the\ndescriptor count:\n\n\trep_max_zones = (ALIGN((u64)alloc_len, RZONES_DESC_HD) -\n\t\t\t RZONES_DESC_HD) \u003e\u003e ilog2(RZONES_DESC_HD);\n\tarr_len = (u64)RZONES_DESC_HD * (rep_max_zones + 1);\n\nFor alloc_len in 0xFFFFFFC1..0xFFFFFFFF, ALIGN() rounds up to\n0x100000000, so arr_len is 4 GB. On 32-bit, kzalloc()\u0027s size_t is 32-bit\nand truncates 0x100000000 to 0; kzalloc(0) returns ZERO_SIZE_PTR, which\npasses the !arr check, and desc = arr + 64 is then dereferenced in the\nloop -\u003e out-of-bounds write / panic.\n\nClamp rep_max_zones to devip-\u003enr_zones. The loop already stops at\nsdebug_capacity (after nr_zones zones), so a report can never hold more\nthan nr_zones descriptors; the clamp does not change the report, it only\nbounds arr_len to (nr_zones + 1) * RZONES_DESC_HD, a real device\nproperty that can never reach 0x100000000."
}
],
"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 - The bug is reached by sending a crafted ZONE IN REPORT ZONES SCSI CDB through local SG_IO/BSG ioctl on a scsi_debug zoned LUN; scsi_debug is a pseudo host simulator with no native network protocol handler.\nAC:L - Once scsi_debug is loaded in host-managed zoned mode, a single REPORT ZONES command with ALLOCATION LENGTH 1-63 reliably underflows rep_max_zones and forces heap writes past a tiny kzalloc buffer; no races or victim-dependent timing are required.\nPR:L - ZBC_IN is whitelisted in scsi_cmd_allowed() without CAP_SYS_RAWIO, so any local user who can open the scsi_debug /dev/sg or BSG node (e.g., disk group) can issue the malicious CDB; module load and zoned setup are environmental, not exploit-time privileges.\nUI:N - Exploitation requires only the attacker issuing SG_IO/BSG with a malicious REPORT ZONES CDB; no separate victim interaction such as mounting media or clicking a prompt is needed.\nS:U - The out-of-bounds write corrupts kernel heap memory in the same host kernel security authority; it is not a VM escape, IOMMU bypass, or other cross-boundary compromise.\nC:H - The kmalloc heap out-of-bounds write can corrupt adjacent slab objects and be groomed into arbitrary kernel memory disclosure primitives; per kernel guidance, exploitable out-of-bounds writes warrant High confidentiality impact.\nI:H - Attacker-controlled REPORT ZONES allocation length drives rep_max_zones and causes repeated 64-byte descriptor writes far beyond the allocated buffer, providing a kernel heap out-of-bounds write suitable for control-data corruption and privilege escalation.\nA:H - Writing zone descriptors from arr+64 when the buffer is smaller than 64 bytes immediately corrupts out-of-bounds kernel memory and commonly triggers KASAN faults, kernel oops, or panic, satisfying High availability impact."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-23T12:47:20.125Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/7b615fc139e35c81077046df44725c532f7e2404"
},
{
"url": "https://git.kernel.org/stable/c/5d3e1d006bbb543259f9e31824caadbfff6a5465"
},
{
"url": "https://git.kernel.org/stable/c/49e5b25a0b74dbac595f122e5608fdce2918cc4e"
},
{
"url": "https://git.kernel.org/stable/c/495058429ca55ab7fcc21977b63b92907ad68066"
},
{
"url": "https://git.kernel.org/stable/c/2047ed09bf13453b7d6f9431b112ec07984dd69b"
},
{
"url": "https://git.kernel.org/stable/c/d6e6da6bc3b53231fac77ffab428da8173ee729c"
},
{
"url": "https://git.kernel.org/stable/c/93dde0bf2f39a0f9f57fd610aa3201ce5b753433"
}
],
"title": "scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74470",
"datePublished": "2026-08-15T12:27:07.504Z",
"dateReserved": "2026-08-15T05:44:03.902Z",
"dateUpdated": "2026-08-23T12:47:20.125Z",
"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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