{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74470", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.902Z", "datePublished": "2026-08-15T12:27:07.504Z", "dateUpdated": "2026-08-23T12:47:20.125Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-23T12:47:20.125Z" }, "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) >> 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()'s 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 -> out-of-bounds write / panic.\n\nClamp rep_max_zones to devip->nr_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": { "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 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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/scsi/scsi_debug.c" ], "versions": [ { "version": "ebacb44cb2042b90951140eda806bedad23ef554", "lessThan": "7b615fc139e35c81077046df44725c532f7e2404", "status": "affected", "versionType": "git" }, { "version": "7db0e0c8190a086ef92ce5bb960836cde49540aa", "lessThan": "5d3e1d006bbb543259f9e31824caadbfff6a5465", "status": "affected", "versionType": "git" }, { "version": "7db0e0c8190a086ef92ce5bb960836cde49540aa", "lessThan": "49e5b25a0b74dbac595f122e5608fdce2918cc4e", "status": "affected", "versionType": "git" }, { "version": "7db0e0c8190a086ef92ce5bb960836cde49540aa", "lessThan": "495058429ca55ab7fcc21977b63b92907ad68066", "status": "affected", "versionType": "git" }, { "version": "7db0e0c8190a086ef92ce5bb960836cde49540aa", "lessThan": "2047ed09bf13453b7d6f9431b112ec07984dd69b", "status": "affected", "versionType": "git" }, { "version": "7db0e0c8190a086ef92ce5bb960836cde49540aa", "lessThan": "d6e6da6bc3b53231fac77ffab428da8173ee729c", "status": "affected", "versionType": "git" }, { "version": "7db0e0c8190a086ef92ce5bb960836cde49540aa", "lessThan": "93dde0bf2f39a0f9f57fd610aa3201ce5b753433", "status": "affected", "versionType": "git" }, { "version": "c4d2d7c935a4ad20e8e726ca10499cefe4537103", "status": "affected", "versionType": "git" }, { "version": "5.15.8", "lessThan": "5.15.217", "status": "affected", "versionType": "semver" }, { "version": "5.10.85", "lessThan": "5.11", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/scsi/scsi_debug.c" ], "versions": [ { "version": "5.16", "status": "affected" }, { "version": "0", "lessThan": "5.16", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.217", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.151", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.103", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.44", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.8", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "5.15.8", "versionEndExcluding": "5.15.217" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.6.151" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.12.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.18.44" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "7.1.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.85" } ] } ] } ], "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" } } } }