FKIE_CVE-2026-89920

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-10-30 13:20
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Fix memory corruption by not reinjecting CK machine checks Channel-subsystem damage machine checks are for the host channel subsystem. The guest channel subsystem is emulated in the userspace VMM. There is no point in forwarding such machine checks into the guest. This also simplifies the machine check reinjection and avoids kfree of a stack variable as reported by sashiko. There might be still machine checks that have the ck bit set with another bit (like instruction damage), mask out the CK bit in s390_backup_mcck_info(), like the CP and ED bits already are.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/045f3e95a0deccb277c29bd003e1d43c0ad40c90
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/546dde823a36d7283dcf46127c2f3d093443860f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5c63e2ed840c85e27172ab78e7db3ac77fba281b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6ee52d3af2a1bf70349cf3f860933c8d221e229a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7077ec953996acc04b49d1dfc43df1c1a2a74395
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b7631982fb65dd355acd18e62b384bc8125e9c44
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/include/asm/nmi.h",
            "arch/s390/kernel/nmi.c",
            "arch/s390/kvm/interrupt.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "045f3e95a0deccb277c29bd003e1d43c0ad40c90",
              "status": "affected",
              "version": "4d62fcc0b692e3b4058d7d138114c27cd8b011f7",
              "versionType": "git"
            },
            {
              "lessThan": "5c63e2ed840c85e27172ab78e7db3ac77fba281b",
              "status": "affected",
              "version": "4d62fcc0b692e3b4058d7d138114c27cd8b011f7",
              "versionType": "git"
            },
            {
              "lessThan": "b7631982fb65dd355acd18e62b384bc8125e9c44",
              "status": "affected",
              "version": "4d62fcc0b692e3b4058d7d138114c27cd8b011f7",
              "versionType": "git"
            },
            {
              "lessThan": "6ee52d3af2a1bf70349cf3f860933c8d221e229a",
              "status": "affected",
              "version": "4d62fcc0b692e3b4058d7d138114c27cd8b011f7",
              "versionType": "git"
            },
            {
              "lessThan": "7077ec953996acc04b49d1dfc43df1c1a2a74395",
              "status": "affected",
              "version": "4d62fcc0b692e3b4058d7d138114c27cd8b011f7",
              "versionType": "git"
            },
            {
              "lessThan": "546dde823a36d7283dcf46127c2f3d093443860f",
              "status": "affected",
              "version": "4d62fcc0b692e3b4058d7d138114c27cd8b011f7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/include/asm/nmi.h",
            "arch/s390/kernel/nmi.c",
            "arch/s390/kvm/interrupt.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.13"
            },
            {
              "lessThan": "4.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: Fix memory corruption by not reinjecting CK machine checks\n\nChannel-subsystem damage machine checks are for the host channel\nsubsystem. The guest channel subsystem is emulated in the userspace VMM.\nThere is no point in forwarding such machine checks into the guest.\n\nThis also simplifies the machine check reinjection and avoids kfree of a\nstack variable as reported by sashiko.  There might be still machine\nchecks that have the ck bit set with another bit (like instruction\ndamage), mask out the CK bit in s390_backup_mcck_info(), like the CP and\nED bits already are."
    }
  ],
  "id": "CVE-2026-89920",
  "lastModified": "2026-10-30T13:20:35.690",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.1,
        "impactScore": 6.0,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-16T11:17:01.073",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/045f3e95a0deccb277c29bd003e1d43c0ad40c90"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/546dde823a36d7283dcf46127c2f3d093443860f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5c63e2ed840c85e27172ab78e7db3ac77fba281b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6ee52d3af2a1bf70349cf3f860933c8d221e229a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7077ec953996acc04b49d1dfc43df1c1a2a74395"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b7631982fb65dd355acd18e62b384bc8125e9c44"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • 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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.