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GHSA-XRCV-F2MV-23J2

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 15:31

Details

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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89919"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:17:00Z",
    "severity": "HIGH"
  },
  "details": "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": "GHSA-xrcv-f2mv-23j2",
  "modified": "2026-09-16T15:31:02Z",
  "published": "2026-09-16T12:30:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89919"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ae452b990e0544425f77045351c56e77158858e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/da07a751efa4583385f9f0f47113549fe8871242"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2026-09-16 10:32 – Updated: 2026-09-16 14:40

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

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/ae452b990e0544425…
https://git.kernel.org/stable/c/da07a751efa458338…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 0ee4ddc1647b8b3b9e7a94d798a1774a764428c1 , < ae452b990e0544425f77045351c56e77158858e7 (git) Affected: 0ee4ddc1647b8b3b9e7a94d798a1774a764428c1 , < da07a751efa4583385f9f0f47113549fe8871242 (git)
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"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ae452b990e0544425f77045351c56e77158858e7",
              "status": "affected",
              "version": "0ee4ddc1647b8b3b9e7a94d798a1774a764428c1",
              "versionType": "git"
            },
            {
              "lessThan": "da07a751efa4583385f9f0f47113549fe8871242",
              "status": "affected",
              "version": "0ee4ddc1647b8b3b9e7a94d798a1774a764428c1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kvm/kvm-s390.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "lessThan": "7.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "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"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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GHSA-XRCV-F2MV-23J2

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

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