{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  arm64: Don't read GMID_EL1 when MTE is disabled  __cpuinfo_store_cpu() gates the GMID_EL1 read on the raw ID_AA64PFR1_EL1, so it reads the register even when the kernel has disabled MTE (CONFIG_ARM64_MTE=n or arm64.nomte). KVM sets HCR_EL2.TID5 in that case, and pKVM injects an UNDEF the host cannot handle:    Internal error: Oops - Undefined instruction: 0000000002000000 [#1]  SMP   pc : __cpuinfo_store_cpu+0xf4/0x264   Kernel panic - not syncing: Attempted to kill the idle task!  Only pKVM reaches it, and only after a CPU is offlined and brought back online: its CPU_ON relay sets the host HCR before the CPU enters EL1, while plain nVHE sets it at CPUHP_AP_KVM_ONLINE.  Gate the read on the CPU's own ID_AA64PFR1_EL1 with the command-line override applied, and on CONFIG_ARM64_MTE, which no register reflects. The boot CPU stores its registers before init_cpu_features() strips an unsafe override, so clamp against the hardware value here too.",
  "id": "DEBIAN-CVE-2026-89981",
  "modified": "2026-09-17T04:47:37.871760291Z",
  "published": "2026-09-16T11:17:09.037Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-89981"
    }
  ],
  "upstream": [
    "CVE-2026-89981"
  ]
}