CVE-2026-89919 (GCVE-0-2026-89919)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:32 – Updated: 2026-09-16 14:40
VLAI
Title
KVM: s390: keyop: use mmu_lock to read gmap->asce
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: s390: keyop: use mmu_lock to read gmap->asce Every other dat_* consumer in this file (kvm_s390_get_skeys, set_skeys, get_cmma_bits, set_cmma_bits, MEM_CLR_CMMA, kvm_s390_fixup_prefix, kvm_test_age_gfn, kvm_age_gfn) reads kvm->arch.gmap->asce *inside* the mmu_lock read-side. keyop is the only outlier. gmap->asce is mutated under write_lock(mmu_lock) by gmap_set_limit() and keyop might use a stale asce value for walking as KVM_S390_KEYOP and KVM_S390_VM_MEM_LIMIT_SIZE can run concurrently. This can result in memory corruption.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0ee4ddc1647b8b3b9e7a94d798a1774a764428c1 , < ae452b990e0544425f77045351c56e77158858e7 (git)
Affected: 0ee4ddc1647b8b3b9e7a94d798a1774a764428c1 , < da07a751efa4583385f9f0f47113549fe8871242 (git)
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Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kvm/kvm-s390.c"
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          "vendor": "Linux",
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              "status": "affected",
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              "version": "7.0"
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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          "nodes": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                },
                {
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: keyop: use mmu_lock to read gmap-\u003easce\n\nEvery other dat_* consumer in this file (kvm_s390_get_skeys,\nset_skeys, get_cmma_bits, set_cmma_bits, MEM_CLR_CMMA,\nkvm_s390_fixup_prefix, kvm_test_age_gfn, kvm_age_gfn) reads\nkvm-\u003earch.gmap-\u003easce *inside* the mmu_lock read-side. keyop is the only\noutlier.\n\ngmap-\u003easce is mutated under write_lock(mmu_lock) by gmap_set_limit()\nand keyop might use a stale asce value for walking as KVM_S390_KEYOP\nand KVM_S390_VM_MEM_LIMIT_SIZE can run concurrently. This can result\nin memory corruption."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Triggered by KVM_S390_KEYOP and KVM_SET_DEVICE_ATTR(KVM_S390_VM_MEM_LIMIT_SIZE) ioctls on a VM fd from /dev/kvm. Not reachable via network packets or guest instruction emulation.\nAC:L - The attacker controls both sides of the race by issuing KEYOP and MEM_LIMIT_SIZE concurrently on a VM they created (before vCPUs exist). No victim state or other uncontrolled condition is required.\nPR:L - Regular (non-ucontrol) VM creation has no capability check; any user who can open /dev/kvm, typically via kvm-group membership, can create a VM and issue these ioctls. CAP_SYS_ADMIN is not required.\nUI:N - The attacker issues the ioctls on a VM they created; no separate user action is required.\nS:U - This is host-userspace-to-host-kernel memory corruption via KVM ioctls, not a guest-to-host escape. MEM_LIMIT_SIZE is rejected once vCPUs exist, and guest storage-key paths already read gmap-\u003easce under mmu_lock.\nC:H - kvm_s390_keyop snapshots gmap-\u003easce without mmu_lock while gmap_set_limit() can free that CRST under write_lock, a page-table use-after-free. Walking reused tables, including ISKE/page_get_storage_key, can disclose kernel memory.\nI:H - SSKE walks the stale ASCE with DAT_WALK_ALLOC and writes via page_set_storage_key and pgste updates. The use-after-free of gmap tables enables writes into recycled kernel memory and storage-key changes on attacker-chosen physical pages.\nA:H - Walking freed CRST/PTE memory or spinning on PGSTE locks derived from reused pages can oops, panic, or hang the host kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:40:12.561Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ae452b990e0544425f77045351c56e77158858e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/da07a751efa4583385f9f0f47113549fe8871242"
        }
      ],
      "title": "KVM: s390: keyop: use mmu_lock to read gmap-\u003easce",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89919",
    "datePublished": "2026-09-16T10:32:14.013Z",
    "dateReserved": "2026-09-11T19:38:34.775Z",
    "dateUpdated": "2026-09-16T14:40:12.561Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-25",
      "epss": "0.00165",
      "percentile": "0.05066"
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    "nvd": {
      "cve": {
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                "product": "Linux",
                "programFiles": [
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
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                  }
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              }
            ],
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          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: keyop: use mmu_lock to read gmap-\u003easce\n\nEvery other dat_* consumer in this file (kvm_s390_get_skeys,\nset_skeys, get_cmma_bits, set_cmma_bits, MEM_CLR_CMMA,\nkvm_s390_fixup_prefix, kvm_test_age_gfn, kvm_age_gfn) reads\nkvm-\u003earch.gmap-\u003easce *inside* the mmu_lock read-side. keyop is the only\noutlier.\n\ngmap-\u003easce is mutated under write_lock(mmu_lock) by gmap_set_limit()\nand keyop might use a stale asce value for walking as KVM_S390_KEYOP\nand KVM_S390_VM_MEM_LIMIT_SIZE can run concurrently. This can result\nin memory corruption."
          }
        ],
        "id": "CVE-2026-89919",
        "lastModified": "2026-09-16T15:18:18.130",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-16T11:17:00.967",
        "references": [
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/da07a751efa4583385f9f0f47113549fe8871242"
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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