Vulnerability-Lookup

FKIE_CVE-2023-53205

Vulnerability from fkie_nvd - Published: 2025-09-15 15:15 - Updated: 2026-08-04 10:18

Severity

7.3 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler We do check for target CPU == -1, but this might change at the time we are going to use it. Hold the physical target CPU in a local variable to avoid out-of-bound accesses to the cpu arrays.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0bc380beb78aa352eadbc21d934dd9606fcee808	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/86bfb18bad60fc468e5f112cbbd918462a8dd435	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a9ccf140a2a03a0ae82be4bdfbdd17bdaea72ff5	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/dc7e0192c470a53d847c79a2796f9ac429477a26	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kvm/diag.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a9ccf140a2a03a0ae82be4bdfbdd17bdaea72ff5",
              "status": "affected",
              "version": "87e28a15c42cc592009c32a8c20e5789059027c2",
              "versionType": "git"
            },
            {
              "lessThan": "86bfb18bad60fc468e5f112cbbd918462a8dd435",
              "status": "affected",
              "version": "87e28a15c42cc592009c32a8c20e5789059027c2",
              "versionType": "git"
            },
            {
              "lessThan": "dc7e0192c470a53d847c79a2796f9ac429477a26",
              "status": "affected",
              "version": "87e28a15c42cc592009c32a8c20e5789059027c2",
              "versionType": "git"
            },
            {
              "lessThan": "0bc380beb78aa352eadbc21d934dd9606fcee808",
              "status": "affected",
              "version": "87e28a15c42cc592009c32a8c20e5789059027c2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kvm/diag.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.121",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.4.*",
              "status": "unaffected",
              "version": "6.4.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "2DD70DCA-71F9-4ADA-BA85-6F161D80109D",
              "versionEndExcluding": "5.15.121",
              "versionStartIncluding": "5.13",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "9BD1D4A1-304D-4187-8178-6D7C0050B1AF",
              "versionEndExcluding": "6.1.39",
              "versionStartIncluding": "5.16",
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            },
            {
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            }
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          "negate": false,
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390/diag: fix racy access of physical cpu number in diag 9c handler\n\nWe do check for target CPU == -1, but this might change at the time we\nare going to use it. Hold the physical target CPU in a local variable to\navoid out-of-bound accesses to the cpu arrays."
    }
  ],
  "id": "CVE-2023-53205",
  "lastModified": "2026-08-04T10:18:57.737",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.3,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 4.7,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      },
      {
        "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"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2025-09-15T15:15:46.977",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/0bc380beb78aa352eadbc21d934dd9606fcee808"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      "url": "https://git.kernel.org/stable/c/86bfb18bad60fc468e5f112cbbd918462a8dd435"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/dc7e0192c470a53d847c79a2796f9ac429477a26"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2023-53205 (GCVE-0-2023-53205)

Vulnerability from cvelistv5 – Published: 2025-09-15 14:21 – Updated: 2026-08-05 09:13

Title

KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler

Summary

Severity

7.3 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/a9ccf140a2a03a0ae…
https://git.kernel.org/stable/c/86bfb18bad60fc468…
https://git.kernel.org/stable/c/dc7e0192c470a53d8…
https://git.kernel.org/stable/c/0bc380beb78aa352e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 87e28a15c42cc592009c32a8c20e5789059027c2 , < a9ccf140a2a03a0ae82be4bdfbdd17bdaea72ff5 (git) Affected: 87e28a15c42cc592009c32a8c20e5789059027c2 , < 86bfb18bad60fc468e5f112cbbd918462a8dd435 (git) Affected: 87e28a15c42cc592009c32a8c20e5789059027c2 , < dc7e0192c470a53d847c79a2796f9ac429477a26 (git) Affected: 87e28a15c42cc592009c32a8c20e5789059027c2 , < 0bc380beb78aa352eadbc21d934dd9606fcee808 (git)
Linux	Linux	Affected: 5.13 Unaffected: 0 , < 5.13 (semver) Unaffected: 5.15.121 , ≤ 5.15.* (semver) Unaffected: 6.1.39 , ≤ 6.1.* (semver) Unaffected: 6.4.4 , ≤ 6.4.* (semver) Unaffected: 6.5 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kvm/diag.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a9ccf140a2a03a0ae82be4bdfbdd17bdaea72ff5",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "86bfb18bad60fc468e5f112cbbd918462a8dd435",
              "status": "affected",
              "version": "87e28a15c42cc592009c32a8c20e5789059027c2",
              "versionType": "git"
            },
            {
              "lessThan": "dc7e0192c470a53d847c79a2796f9ac429477a26",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "0bc380beb78aa352eadbc21d934dd9606fcee808",
              "status": "affected",
              "version": "87e28a15c42cc592009c32a8c20e5789059027c2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kvm/diag.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.121",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.4.*",
              "status": "unaffected",
              "version": "6.4.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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                },
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      "descriptions": [
        {
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390/diag: fix racy access of physical cpu number in diag 9c handler\n\nWe do check for target CPU == -1, but this might change at the time we\nare going to use it. Hold the physical target CPU in a local variable to\navoid out-of-bound accesses to the cpu arrays."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
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            "baseSeverity": "HIGH",
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            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached when a KVM guest on s390 executes privileged DIAG 0x9c, which exits via SIE intercept into kvm_s390_handle_diag \u2192 __diag_time_slice_end_directed on the host; there is no network or adjacent-link entry point.\nAC:L - A multi-vCPU guest attacker controls both sides of the race (spam DIAG 9c from one vCPU while forcing the target vCPU through kvm_arch_vcpu_put so tcpu-\u003ecpu becomes -1) and can retry freely; scoring assumes the worst reasonable deployment with diag9c_forwarding_hz enabled so the forwarding path is live.\nPR:L - Triggering requires only the ability to run a KVM guest (/dev/kvm kvm-group/VMM user or cloud tenant) and issue DIAG from guest supervisor state; that is ordinary unprivileged-vs-host access, not real init-namespace root.\nUI:N - The attacker drives the DIAG 9c spam and target-vCPU scheduling from their own guest with no separate victim action required.\nS:C - A guest-triggered host bug that indexes host kernel cpu arrays (lowcore_ptr/pcpu_devices) crosses the guest/host virtualization boundary and can crash or touch host kernel state outside the guest\u2019s security authority.\nC:L - Winning the race yields a fixed negative-index (-1) out-of-bounds read of host lowcore_ptr/pcpu_devices and a subsequent pointer chase; this is a bounded adjacent host-kernel read without a guest-visible bulk disclosure path, matching C:L rather than C:N or C:H.\nI:N - The vulnerable path only reads OOB array state and may issue a spurious host DIAG 9c yield; there is no out-of-bounds write, UAF store, or other host integrity/control-flow primitive.\nA:H - Dereferencing lowcore_ptr[-1] (often NULL/garbage) or using an invalid pcpu_devices[-1] address can oops/panic the host kernel, so availability impact is High and repeatable whenever the race is won."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T09:13:05.376Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        },
        {
          "url": "https://git.kernel.org/stable/c/0bc380beb78aa352eadbc21d934dd9606fcee808"
        }
      ],
      "title": "KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53205",
    "datePublished": "2025-09-15T14:21:33.560Z",
    "dateReserved": "2025-09-15T13:59:19.068Z",
    "dateUpdated": "2026-08-05T09:13:05.376Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.