{"api_version":"1","generated_at":"2026-07-20T14:43:05+00:00","cve":"CVE-2026-64186","urls":{"html":"https://cve.report/CVE-2026-64186","api":"https://cve.report/api/cve/CVE-2026-64186.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64186","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64186"},"summary":{"title":"iommu/amd: Remove latent out-of-bounds access in IOMMU debugfs","description":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/amd: Remove latent out-of-bounds access in IOMMU debugfs\n\nIn iommu_mmio_write() and iommu_capability_write(), the variables\ndbg_mmio_offset and dbg_cap_offset are declared as int. However, they\nare populated using kstrtou32_from_user(). If a user provides a\nsufficiently large value, it can become a negative integer.\n\nPrior to this patch, the AMD IOMMU debugfs implementation was already\nprotected by different mechanisms.\n\n1. #define OFS_IN_SZ 8 ensures the user string <= 8 bytes, so\n   e.g. 0xffffffff isn't a valid input.\n\n  if (cnt > OFS_IN_SZ)\n     return -EINVAL;\n\n2. Implicit type promotion in iommu_mmio_write(), dbg_mmio_offset is int\n   and iommu->mmio_phys_end is u64\n\n  if (dbg_mmio_offset > iommu->mmio_phys_end - sizeof(u64))\n      return -EINVAL;\n\n3. The show handlers would currently catch the negative number and\n   refuse to perform the read.\n\nReplace kstrtou32_from_user() with kstrtos32_from_user() to parse the\ninput, and check for negative values to explicitly prevent out-of-bounds\nmemory accesses directly in iommu_mmio_write() and\niommu_capability_write().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:18:01","updated_at":"2026-07-19 16:18:01"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/488d2c76bd9f78433a70690d1054bfae3d39a407","name":"https://git.kernel.org/stable/c/488d2c76bd9f78433a70690d1054bfae3d39a407","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8dfd3d8d74435344ee8dc9237596959c8b2a6cbe","name":"https://git.kernel.org/stable/c/8dfd3d8d74435344ee8dc9237596959c8b2a6cbe","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/62f9dfbf1aceae88b03c5ca08f7d36e943939dec","name":"https://git.kernel.org/stable/c/62f9dfbf1aceae88b03c5ca08f7d36e943939dec","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64186","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64186","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7a4ee419e8c144b747a8915856e91a034d7c8f34 488d2c76bd9f78433a70690d1054bfae3d39a407 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7a4ee419e8c144b747a8915856e91a034d7c8f34 62f9dfbf1aceae88b03c5ca08f7d36e943939dec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7a4ee419e8c144b747a8915856e91a034d7c8f34 8dfd3d8d74435344ee8dc9237596959c8b2a6cbe git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.17","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.34 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.11 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/iommu/amd/debugfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"488d2c76bd9f78433a70690d1054bfae3d39a407","status":"affected","version":"7a4ee419e8c144b747a8915856e91a034d7c8f34","versionType":"git"},{"lessThan":"62f9dfbf1aceae88b03c5ca08f7d36e943939dec","status":"affected","version":"7a4ee419e8c144b747a8915856e91a034d7c8f34","versionType":"git"},{"lessThan":"8dfd3d8d74435344ee8dc9237596959c8b2a6cbe","status":"affected","version":"7a4ee419e8c144b747a8915856e91a034d7c8f34","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/iommu/amd/debugfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.17"},{"lessThan":"6.17","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.34","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.34","versionStartIncluding":"6.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.11","versionStartIncluding":"6.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.17","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/amd: Remove latent out-of-bounds access in IOMMU debugfs\n\nIn iommu_mmio_write() and iommu_capability_write(), the variables\ndbg_mmio_offset and dbg_cap_offset are declared as int. However, they\nare populated using kstrtou32_from_user(). If a user provides a\nsufficiently large value, it can become a negative integer.\n\nPrior to this patch, the AMD IOMMU debugfs implementation was already\nprotected by different mechanisms.\n\n1. #define OFS_IN_SZ 8 ensures the user string <= 8 bytes, so\n   e.g. 0xffffffff isn't a valid input.\n\n  if (cnt > OFS_IN_SZ)\n     return -EINVAL;\n\n2. Implicit type promotion in iommu_mmio_write(), dbg_mmio_offset is int\n   and iommu->mmio_phys_end is u64\n\n  if (dbg_mmio_offset > iommu->mmio_phys_end - sizeof(u64))\n      return -EINVAL;\n\n3. The show handlers would currently catch the negative number and\n   refuse to perform the read.\n\nReplace kstrtou32_from_user() with kstrtos32_from_user() to parse the\ninput, and check for negative values to explicitly prevent out-of-bounds\nmemory accesses directly in iommu_mmio_write() and\niommu_capability_write()."}],"providerMetadata":{"dateUpdated":"2026-07-19T15:41:08.054Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/488d2c76bd9f78433a70690d1054bfae3d39a407"},{"url":"https://git.kernel.org/stable/c/62f9dfbf1aceae88b03c5ca08f7d36e943939dec"},{"url":"https://git.kernel.org/stable/c/8dfd3d8d74435344ee8dc9237596959c8b2a6cbe"}],"title":"iommu/amd: Remove latent out-of-bounds access in IOMMU debugfs","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64186","datePublished":"2026-07-19T15:41:08.054Z","dateReserved":"2026-07-19T07:54:57.039Z","dateUpdated":"2026-07-19T15:41:08.054Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:18:01","lastModifiedDate":"2026-07-19 16:18:01","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64186","Ordinal":"1","Title":"iommu/amd: Remove latent out-of-bounds access in IOMMU debugfs","CVE":"CVE-2026-64186","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64186","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/amd: Remove latent out-of-bounds access in IOMMU debugfs\n\nIn iommu_mmio_write() and iommu_capability_write(), the variables\ndbg_mmio_offset and dbg_cap_offset are declared as int. However, they\nare populated using kstrtou32_from_user(). If a user provides a\nsufficiently large value, it can become a negative integer.\n\nPrior to this patch, the AMD IOMMU debugfs implementation was already\nprotected by different mechanisms.\n\n1. #define OFS_IN_SZ 8 ensures the user string <= 8 bytes, so\n   e.g. 0xffffffff isn't a valid input.\n\n  if (cnt > OFS_IN_SZ)\n     return -EINVAL;\n\n2. Implicit type promotion in iommu_mmio_write(), dbg_mmio_offset is int\n   and iommu->mmio_phys_end is u64\n\n  if (dbg_mmio_offset > iommu->mmio_phys_end - sizeof(u64))\n      return -EINVAL;\n\n3. The show handlers would currently catch the negative number and\n   refuse to perform the read.\n\nReplace kstrtou32_from_user() with kstrtos32_from_user() to parse the\ninput, and check for negative values to explicitly prevent out-of-bounds\nmemory accesses directly in iommu_mmio_write() and\niommu_capability_write().","Type":"Description","Title":"iommu/amd: Remove latent out-of-bounds access in IOMMU debugfs"}]}}}