{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "f35abcbb8a084db4c24b66ccc8db0405c08e2f61"
            },
            {
              "fixed": "d2d22ff377cd43f2e9660426ff22e3cd4c534637"
            },
            {
              "fixed": "5445d64199626974269fcdf347769ad44b0bb53b"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89981.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: Don't read GMID_EL1 when MTE is disabled\n\n__cpuinfo_store_cpu() gates the GMID_EL1 read on the raw\nID_AA64PFR1_EL1, so it reads the register even when the kernel has\ndisabled MTE (CONFIG_ARM64_MTE=n or arm64.nomte). KVM sets HCR_EL2.TID5\nin that case, and pKVM injects an UNDEF the host cannot handle:\n\n  Internal error: Oops - Undefined instruction: 0000000002000000 [#1]  SMP\n  pc : __cpuinfo_store_cpu+0xf4/0x264\n  Kernel panic - not syncing: Attempted to kill the idle task!\n\nOnly pKVM reaches it, and only after a CPU is offlined and brought back\nonline: its CPU_ON relay sets the host HCR before the CPU enters EL1,\nwhile plain nVHE sets it at CPUHP_AP_KVM_ONLINE.\n\nGate the read on the CPU's own ID_AA64PFR1_EL1 with the command-line\noverride applied, and on CONFIG_ARM64_MTE, which no register reflects.\nThe boot CPU stores its registers before init_cpu_features() strips an\nunsafe override, so clamp against the hardware value here too.",
  "id": "CVE-2026-89981",
  "modified": "2026-09-18T03:30:22.977063149Z",
  "published": "2026-09-16T10:32:58.056Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5445d64199626974269fcdf347769ad44b0bb53b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d2d22ff377cd43f2e9660426ff22e3cd4c534637"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89981.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89981"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "arm64: Don't read GMID_EL1 when MTE is disabled"
}