{"id":"CVE-2026-74470","state":"PUBLISHED","title":"scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write","description":"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.","publishedAt":"2026-08-15T12:27:07.504Z","updatedAt":"2026-10-16T19:05:47.666Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ebacb44cb2042b90951140eda806bedad23ef554","status":"affected","lessThan":"7b615fc139e35c81077046df44725c532f7e2404","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"5d3e1d006bbb543259f9e31824caadbfff6a5465","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"49e5b25a0b74dbac595f122e5608fdce2918cc4e","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"495058429ca55ab7fcc21977b63b92907ad68066","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"2047ed09bf13453b7d6f9431b112ec07984dd69b","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"d6e6da6bc3b53231fac77ffab428da8173ee729c","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"93dde0bf2f39a0f9f57fd610aa3201ce5b753433","versionType":"git"},{"version":"c4d2d7c935a4ad20e8e726ca10499cefe4537103","status":"affected","versionType":"git"},{"version":"5.15.8","status":"affected","lessThan":"5.15.217","versionType":"semver"},{"version":"5.10.85","status":"affected","lessThan":"5.11","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/scsi_debug.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.16","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.151","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/scsi_debug.c"]}],"references":["https://git.kernel.org/stable/c/7b615fc139e35c81077046df44725c532f7e2404","https://git.kernel.org/stable/c/5d3e1d006bbb543259f9e31824caadbfff6a5465","https://git.kernel.org/stable/c/49e5b25a0b74dbac595f122e5608fdce2918cc4e","https://git.kernel.org/stable/c/495058429ca55ab7fcc21977b63b92907ad68066","https://git.kernel.org/stable/c/2047ed09bf13453b7d6f9431b112ec07984dd69b","https://git.kernel.org/stable/c/d6e6da6bc3b53231fac77ffab428da8173ee729c","https://git.kernel.org/stable/c/93dde0bf2f39a0f9f57fd610aa3201ce5b753433"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74470.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74470","state":"PUBLISHED","datePublished":"2026-08-15T12:27:07.504Z","dateUpdated":"2026-10-16T19:05:47.666Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.902Z"},"containers":{"cna":{"title":"scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write","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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ebacb44cb2042b90951140eda806bedad23ef554","status":"affected","lessThan":"7b615fc139e35c81077046df44725c532f7e2404","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"5d3e1d006bbb543259f9e31824caadbfff6a5465","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"49e5b25a0b74dbac595f122e5608fdce2918cc4e","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"495058429ca55ab7fcc21977b63b92907ad68066","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"2047ed09bf13453b7d6f9431b112ec07984dd69b","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"d6e6da6bc3b53231fac77ffab428da8173ee729c","versionType":"git"},{"version":"7db0e0c8190a086ef92ce5bb960836cde49540aa","status":"affected","lessThan":"93dde0bf2f39a0f9f57fd610aa3201ce5b753433","versionType":"git"},{"version":"c4d2d7c935a4ad20e8e726ca10499cefe4537103","status":"affected","versionType":"git"},{"version":"5.15.8","status":"affected","lessThan":"5.15.217","versionType":"semver"},{"version":"5.10.85","status":"affected","lessThan":"5.11","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/scsi_debug.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.16","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.151","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/scsi_debug.c"]}],"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"}],"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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-23T12:47:20.125Z"},"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74470","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:57:17.506626Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:05:47.666Z"}}]}}}