Vulnerability-Lookup

GHSA-4QF9-G5CF-CX9J

Vulnerability from github – Published: 2026-05-19 15:31 – Updated: 2026-05-19 18:32

Details

The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still left a race window, when a HVM or PVH guest does a grant table version change from v2 to v1 in parallel with mapping the status page(s) via XENMEM_add_to_physmap. Some of the status pages may then be freed while mappings of them would still be inserted into the guest's secondary (P2M) page tables.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23558"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-362"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-19T14:16:38Z",
    "severity": "HIGH"
  },
  "details": "The adjustments made for XSA-379 as well as those subsequently becoming\nXSA-387 still left a race window, when a HVM or PVH guest does a grant\ntable version change from v2 to v1 in parallel with mapping the status\npage(s) via XENMEM_add_to_physmap.  Some of the status pages may then be\nfreed while mappings of them would still be inserted into the guest\u0027s\nsecondary (P2M) page tables.",
  "id": "GHSA-4qf9-g5cf-cx9j",
  "modified": "2026-05-19T18:32:08Z",
  "published": "2026-05-19T15:31:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23558"
    },
    {
      "type": "WEB",
      "url": "https://xenbits.xenproject.org/xsa/advisory-486.html"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/04/28/13"
    },
    {
      "type": "WEB",
      "url": "http://xenbits.xen.org/xsa/advisory-486.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-23558 (GCVE-0-2026-23558)

Vulnerability from cvelistv5 – Published: 2026-05-19 12:49 – Updated: 2026-05-20 03:55

Title

grant table v2 race in status page mapping

Summary

Severity

7.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-19 00:00 UTC

CWE

CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Assigner

XEN mitre root Scorecard

References

3 references

URL	Tags
https://xenbits.xenproject.org/xsa/advisory-486.html
http://www.openwall.com/lists/oss-security/2026/0…
http://xenbits.xen.org/xsa/advisory-486.html

Impacted products

1 product

Vendor	Product	Version
Xen	Xen	Unknown: consult Xen advisory XSA-486

Date Public

2026-04-28 12:00

Credits

This issue was discovered by Claude Opus 4.6 and diagnosed as a security issue by Rafal Wojtczuk.

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JSON

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{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-05-19T13:06:51.044Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/04/28/13"
          },
          {
            "url": "http://xenbits.xen.org/xsa/advisory-486.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-23558",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-19T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-362",
                "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-20T03:55:35.327Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Xen",
          "vendor": "Xen",
          "versions": [
            {
              "status": "unknown",
              "version": "consult Xen advisory XSA-486"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "value": "All Xen versions from 4.0 onwards are affected.  Xen versions 3.4 and\nolder are not affected.\n\nOnly x86 HVM and PVH guests permitted to use grant table version 2\ninterfaces can leverage this vulnerability.  x86 PV guests cannot\nleverage this vulnerability.  On Arm, grant table v2 use is explicitly\nunsupported."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Claude Opus 4.6 and diagnosed as a security\nissue by Rafal Wojtczuk."
        }
      ],
      "datePublic": "2026-04-28T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "The adjustments made for XSA-379 as well as those subsequently becoming\nXSA-387 still left a race window, when a HVM or PVH guest does a grant\ntable version change from v2 to v1 in parallel with mapping the status\npage(s) via XENMEM_add_to_physmap.  Some of the status pages may then be\nfreed while mappings of them would still be inserted into the guest\u0027s\nsecondary (P2M) page tables."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "Privilege escalation, information leaks, and Denial of Service (DoS) up\nto affecting the entire host cannot be excluded."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-19T12:49:54.652Z",
        "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "shortName": "XEN"
      },
      "references": [
        {
          "url": "https://xenbits.xenproject.org/xsa/advisory-486.html"
        }
      ],
      "title": "grant table v2 race in status page mapping",
      "workarounds": [
        {
          "lang": "en",
          "value": "Using the \"gnttab=max-ver:1\" hypervisor command line option will avoid\nthe vulnerability.\n\nUsing the \"max_grant_version=1\" guest configuration option for HVM and PVH\nguests will also avoid the vulnerability."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
    "assignerShortName": "XEN",
    "cveId": "CVE-2026-23558",
    "datePublished": "2026-05-19T12:49:54.652Z",
    "dateReserved": "2026-01-14T13:07:36.961Z",
    "dateUpdated": "2026-05-20T03:55:35.327Z",
    "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.

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.

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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.

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GHSA-4QF9-G5CF-CX9J

CVE-2026-23558 (GCVE-0-2026-23558)

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