{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "7270cc9157f474dfc46750a34c9d7defc686b2eb"
            },
            {
              "fixed": "5cbd8761d001c11ada73b1753d772c4745a70e72"
            },
            {
              "fixed": "9065c1261f8a05c6a7a2d90048c7c0665ab2896d"
            },
            {
              "fixed": "38640bc32be3fcf9526d477155bc19d3f146231f"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.16.0"
            },
            {
              "fixed": "6.18.52"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "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-2026-89917.json"
  },
  "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.",
  "id": "CVE-2026-89917",
  "modified": "2026-09-18T03:30:49.375053948Z",
  "published": "2026-09-16T10:32:12.629Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/38640bc32be3fcf9526d477155bc19d3f146231f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5cbd8761d001c11ada73b1753d772c4745a70e72"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9065c1261f8a05c6a7a2d90048c7c0665ab2896d"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89917.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89917"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "KVM: arm64: Handle VNCR TLB invalidation race with vcpu_put() VNCR unmapping"
}