{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-89917",
  "modified": "2026-10-07T14:35:31Z",
  "upstream": [
    "CVE-2026-89917"
  ],
  "published": "2026-09-16T10:32:03Z",
  "summary": "KVM: arm64: Handle VNCR TLB invalidation race with vcpu_put() VNCR unmapping",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Handle VNCR TLB invalidation race with vcpu_put() VNCR unmapping\n\nWhile VNCR TLB invalidation always occurs under the MMU lock,\nvcpu_put() doesn't, while it unmaps the VNCR page.\n\nThe problem is that the invalidation evaluates vncr_tlb::cpu to\ndecide whether an unmapping needs to take place (cpu != -1) before\nperforming it. On the other hand, this_cpu_reset_vncr_fixmap()\nunconditionally unmaps if L1_VNCR_MAPPED is set.\n\nThese two obviously can race, with a TOCTOU pattern on the TLBI\npath, and a BUG_ON() on the vcpu_put() path. And the two can end-up\ncalling vncr_fixmap(-1), with extra lethal effects.\n\nMove the reset of vncr_tlb::cpu to -1 to a common function, and make\nthis update atomic so that only a single thread can reset the field\nand perform the corresponding unmap. The vcpu_put() still need to\nunconditionally unmap the current VNCR to close another ugly race.\n\nFinally, the assignment of vncr_tlb::cpu is moved to be kept in sync\nwith the actual mapping, similar to L1_VNCR_MAPPED being set.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:13",
        "name": "linux"
      },
      "versions": [
        "1:6.18.29-1+rpt1",
        "1:6.18.33-1+rpt1",
        "1:6.18.34-1+rpt1",
        "1:6.18.39-1+rpt1",
        "1:6.18.50-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-2712",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-v8",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-2712",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v8",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-2712",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v8",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-2712",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v8",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-2712",
            "binary_version": "1:6.18.50-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-v8",
            "binary_version": "1:6.18.50-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.50-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.18.29-1+rpt1": {
            "linux_commit": "66318c5b5cd8145a662303af12ed39ac07eb27cc",
            "upstream_version": "6.18.29",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.52"
          },
          "1:6.18.33-1+rpt1": {
            "linux_commit": "95b85bebbedcaedfa7ca79116ed38b7376fba412",
            "upstream_version": "6.18.33",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.52"
          },
          "1:6.18.34-1+rpt1": {
            "linux_commit": "c8c7494100e99ee05b11aaa4f0588a223a63d1af",
            "upstream_version": "6.18.34",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.52"
          },
          "1:6.18.39-1+rpt1": {
            "linux_commit": "60ea684a8ace97bb0db1a16e20753bdd6ab371ff",
            "upstream_version": "6.18.39",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.52"
          },
          "1:6.18.50-1+rpt1": {
            "linux_commit": "cff533aec2fa601846766b32ff57204e0a61bed7",
            "upstream_version": "6.18.50",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.52"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-89917"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5cbd8761d001c11ada73b1753d772c4745a70e72"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9065c1261f8a05c6a7a2d90048c7c0665ab2896d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/38640bc32be3fcf9526d477155bc19d3f146231f"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-16T10:32:03Z"
  }
}