Vulnerability-Lookup

GHSA-Q47X-VHX7-RRVJ

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31

Details

In the Linux kernel, the following vulnerability has been resolved:

KVM: SEV: Check PSC request indices against the actual size of the buffer

When processing Page State Change (PSC) requests, validate the PSC buffer against the effective size of the scratch area, which could be less than the maximum size if the guest provided a pointer that isn't exactly at the start of the GHCB shared buffer.

Severity

9.3 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-63938"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:12Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Check PSC request indices against the actual size of the buffer\n\nWhen processing Page State Change (PSC) requests, validate the PSC buffer\nagainst the effective size of the scratch area, which could be less than\nthe maximum size if the guest provided a pointer that isn\u0027t exactly at the\nstart of the GHCB shared buffer.",
  "id": "GHSA-q47x-vhx7-rrvj",
  "modified": "2026-07-20T15:31:52Z",
  "published": "2026-07-19T18:31:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63938"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/121d88de56bc5c0ba0ce2f6381af67f948a7e7c1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/505a3b94535583e4265360e2621734e355ef263d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5198f70c09a5f6e9e5f5a0a2c6b388f24294b176"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75c8d1d7291268b479794fba5808971dc2f5eaf3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-63938 (GCVE-0-2026-63938)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-07-20 13:41

Title

KVM: SEV: Check PSC request indices against the actual size of the buffer

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Check PSC request indices against the actual size of the buffer When processing Page State Change (PSC) requests, validate the PSC buffer against the effective size of the scratch area, which could be less than the maximum size if the guest provided a pointer that isn't exactly at the start of the GHCB shared buffer.

Severity

9.3 (Critical)


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

Assigner

Linux

References

4 references

URL	Tags
https://git.kernel.org/stable/c/5198f70c09a5f6e9e…
https://git.kernel.org/stable/c/75c8d1d7291268b47…
https://git.kernel.org/stable/c/505a3b94535583e42…
https://git.kernel.org/stable/c/121d88de56bc5c0ba…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 5198f70c09a5f6e9e5f5a0a2c6b388f24294b176 (git) Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 75c8d1d7291268b479794fba5808971dc2f5eaf3 (git) Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 505a3b94535583e4265360e2621734e355ef263d (git) Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 121d88de56bc5c0ba0ce2f6381af67f948a7e7c1 (git)
Linux	Linux	Affected: 6.11 Unaffected: 0 , < 6.11 (semver) Unaffected: 6.12.93 , ≤ 6.12.* (semver) Unaffected: 6.18.35 , ≤ 6.18.* (semver) Unaffected: 7.0.12 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5198f70c09a5f6e9e5f5a0a2c6b388f24294b176",
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "versionType": "git"
            },
            {
              "lessThan": "75c8d1d7291268b479794fba5808971dc2f5eaf3",
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "versionType": "git"
            },
            {
              "lessThan": "505a3b94535583e4265360e2621734e355ef263d",
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "versionType": "git"
            },
            {
              "lessThan": "121d88de56bc5c0ba0ce2f6381af67f948a7e7c1",
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.93",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.35",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.12",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
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        }
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Check PSC request indices against the actual size of the buffer\n\nWhen processing Page State Change (PSC) requests, validate the PSC buffer\nagainst the effective size of the scratch area, which could be less than\nthe maximum size if the guest provided a pointer that isn\u0027t exactly at the\nstart of the GHCB shared buffer."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T13:41:40.069Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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        },
        {
          "url": "https://git.kernel.org/stable/c/505a3b94535583e4265360e2621734e355ef263d"
        },
        {
          "url": "https://git.kernel.org/stable/c/121d88de56bc5c0ba0ce2f6381af67f948a7e7c1"
        }
      ],
      "title": "KVM: SEV: Check PSC request indices against the actual size of the buffer",
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        "engine": "bippy-1.2.0"
      }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63938",
    "datePublished": "2026-07-19T14:55:35.168Z",
    "dateReserved": "2026-07-19T07:54:57.022Z",
    "dateUpdated": "2026-07-20T13:41:40.069Z",
    "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.

Action not permitted

GHSA-Q47X-VHX7-RRVJ

CVE-2026-63938 (GCVE-0-2026-63938)

Tags

Sightings

Nomenclature