{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-80921",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-80921"
  ],
  "published": "2026-09-09T16:19:47Z",
  "summary": "KVM: s390: vsie: zero stale crypto bits",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: vsie: zero stale crypto bits\n\nWhen shadowing crypto access bits from a format0 apcb (crycb 0 or 1),\nthe bits 64..255 are unchanged from whatever is in the vsie page in the\ncrycb and thus in the apcb. This gives a nested guest potential access\nto a device no longer available. Zero out the remaining bits.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.187",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-80921"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-10T05:52:04Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 8.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The bug is reached when an s390 KVM guest executes the privileged SIE instruction (B2/14), intercepted through handle_instruction() to kvm_s390_handle_vsie() and setup_apcb10(); that is a local guest/KVM ioctl path with no network, Bluetooth, or USB exposure.\nAC:L - An L1 guest that first runs a FORMAT-2 nested SCB (setup_apcb11 fills all 256 APCB bits) and then a FORMAT-0/1 SCB on a recycled vsie page hits setup_apcb10() deterministically; get_vsie_page() reuses pages without clearing crycb, so leftover bits 64-255 persist with no race or uncontrolled memory layout.\nPR:L - SIE requires guest supervisor state, i.e. the tenant guest kernel or an unprivileged host kvm-group user running QEMU, not host root; kvm_s390_handle_vsie() has no host capability gate, and user namespaces cannot substitute for this path, so privileges stay Low rather than High.\nUI:N - The attacker guest issues SIE and uses the over-permissive shadow APCB itself; vsie page reuse and crycb shadowing run automatically inside KVM with no victim mount, click, or other user action.\nS:C - Leftover APCB bits grant a nested guest millicode-enforced access to host AP adapters/domains outside its delegated matrix, crossing the KVM nested-virt and vfio-ap passthrough boundary into another guest's or the host zcrypt authority, equivalent to an IOMMU/device isolation bypass.\nC:H - Unauthorized APQNs let the nested guest issue NQAP/DQAP against queues that may now belong to the host zcrypt stack or another tenant, disclosing cryptographic request/response data and key material on those adapters/domains.\nI:H - The nested guest can enqueue arbitrary AP requests and change hardware queue state on adapters and domains 64-255 that the current shadow should have cleared, corrupting crypto operations the host believes are exclusive to another consumer.\nA:H - With those leftover APQNs the nested guest can PQAP(ZAPQ)-reset or flood shared queues, denying host or sibling-guest crypto services (pkey, secure-key LUKS, openCryptoki) that depend on the same physical adapter/domain."
    }
  }
}