{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-81016", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.813Z", "datePublished": "2026-09-11T19:43:04.740Z", "dateUpdated": "2026-10-21T12:47:24.488Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:47:24.488Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nplatform/x86/amd/pmc: Propagate SMU errors and validate S2D address\n\namd_stb_s2d_init() discards the return value of several S2D SMU commands.\nWhen the SMU refuses a command (e.g. \"SMU cmd failed. err: 0xff\") the\nfailure is only noticed indirectly - if at all - and reported as -EIO,\nmasking the real error.\n\nMore seriously, the S2D_PHYS_ADDR_LOW/HIGH return values are ignored, so\non failure phys_addr_low/hi are left uninitialised and the assembled\naddress is passed straight to devm_ioremap(). When the SMU leaves them at\nzero this maps physical address 0 and trips the ioremap-on-RAM warning:\n\n amd_pmc AMDI000B:00: SMU cmd failed. err: 0xff\n ioremap on RAM at 0x0000000000000000 - 0x0000000000ffffff\n WARNING: CPU: 13 PID: 4592 at arch/x86/mm/ioremap.c:...\n\nCheck the return value of each SMU command and propagate it, and reject a\nzero physical address before calling devm_ioremap()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.7, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - amd_stb_s2d_init() runs from amd_pmc_probe() on the AMD PMC ACPI platform driver (AMDI0005–AMDI000C and related IDs) during local device bind or module load; the SMU mailbox commands and devm_ioremap() are not reachable from network, Bluetooth, Wi-Fi, or USB packet paths.\nAC:L - On affected AMD platforms where SMU accepts S2D_TELEMETRY_SIZE but rejects S2D_PHYS_ADDR_LOW/HIGH (observed err 0xff), ignored failures leave phys_addr_low/hi uninitialized or zero and the subsequent ioremap is deterministic; stack zeroing makes address 0 reliable, with no race or attacker-uncontrollable layout.\nPR:N - The SMU queries and devm_ioremap() execute automatically in amd_pmc_probe() during ACPI/udev bind with no capable() check; enable_stb=1 is the vulnerable STB debug deployment (kernel cmdline or modprobe), after which kernel context runs the path without a user account or namespace privilege.\nUI:N - No victim interaction is required; the invalid ioremap occurs during automatic amd_pmc probe at boot or module load when STB is enabled, before any debugfs open, mount, or other user action.\nS:U - The bad physical-address ioremap, kernel warning, and any subsequent STB debugfs copy occur entirely inside the host kernel PMC driver; this is not a VM escape, IOMMU/DMA boundary bypass, or other cross-authority breakout.\nC:H - Ignored SMU failures pass uninitialized phys_addr_low/hi to devm_ioremap() for up to 16MB (S2D_TELEMETRY_DRAMBYTES_MAX); a non-RAM physical address creates a mapping that amd_stb_debugfs_open_v2 copies to userspace via memcpy_fromio on the 0644 stb_read node, yielding a large physical-memory disclosure.\nI:N - The driver only memcpy_fromio()s the STB mapping and never writes through stb_virt_addr; ioremap of RAM at address 0 is rejected, and there is no out-of-bounds write, use-after-free, or other kernel integrity or control-flow primitive.\nA:H - devm_ioremap() of physical address 0 hits WARN_ONCE in arch/x86/mm/ioremap.c, which panics under panic_on_warn; when the mapping fails, stb_virt_addr stays NULL while debugfs stb_read remains, so a later open does memcpy_fromio(NULL) and oopses the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/platform/x86/amd/pmc/mp1_stb.c" ], "versions": [ { "version": "3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d", "lessThan": "85ef9d4c384c1d143c51580933674d94dba3b8d9", "status": "affected", "versionType": "git" }, { "version": "3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d", "lessThan": "638e1ca5d4e2b4fdbb209db64926d013b34f3b79", "status": "affected", "versionType": "git" }, { "version": "3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d", "lessThan": "8178f59d76570b152d836bde07f5997f15861f04", "status": "affected", "versionType": "git" }, { "version": "3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d", "lessThan": "775d4cde1f9737796ce7d8393521e9e8c5b49891", "status": "affected", "versionType": "git" }, { "version": "3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d", "lessThan": "0225c1d637687b03726f00ac65b6def843d2c464", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/platform/x86/amd/pmc/mp1_stb.c" ], "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "lessThan": "5.18", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "5.18", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/85ef9d4c384c1d143c51580933674d94dba3b8d9" }, { "url": "https://git.kernel.org/stable/c/638e1ca5d4e2b4fdbb209db64926d013b34f3b79" }, { "url": "https://git.kernel.org/stable/c/8178f59d76570b152d836bde07f5997f15861f04" }, { "url": "https://git.kernel.org/stable/c/775d4cde1f9737796ce7d8393521e9e8c5b49891" }, { "url": "https://git.kernel.org/stable/c/0225c1d637687b03726f00ac65b6def843d2c464" } ], "title": "platform/x86/amd/pmc: Propagate SMU errors and validate S2D address", "x_generator": { "engine": "bippy-1.2.0" } } } }