Vulnerability-Lookup

GHSA-H6VW-38XQ-3XWX

Vulnerability from github – Published: 2026-03-23 09:30 – Updated: 2026-03-23 15:30

Details

Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.

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-2026-23554"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-367"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-23T07:16:07Z",
    "severity": "HIGH"
  },
  "details": "The Intel EPT paging code uses an optimization to defer flushing of any cached\nEPT state until the p2m lock is dropped, so that multiple modifications done\nunder the same locked region only issue a single flush.\n\nFreeing of paging structures however is not deferred until the flushing is\ndone, and can result in freed pages transiently being present in cached state.\nSuch stale entries can point to memory ranges not owned by the guest, thus\nallowing access to unintended memory regions.",
  "id": "GHSA-h6vw-38xq-3xwx",
  "modified": "2026-03-23T15:30:43Z",
  "published": "2026-03-23T09:30:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23554"
    },
    {
      "type": "WEB",
      "url": "https://xenbits.xenproject.org/xsa/advisory-480.html"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/03/17/6"
    },
    {
      "type": "WEB",
      "url": "http://xenbits.xen.org/xsa/advisory-480.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-2026-23554 (GCVE-0-2026-23554)

Vulnerability from cvelistv5 – Published: 2026-03-23 06:56 – Updated: 2026-03-23 14:19

Title

Use after free of paging structures in EPT

Summary

The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush. Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.

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 2026-03-23 14:18 UTC

CWE

CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

Assigner

XEN CNA under the mitre root

CNA scorecard D 56/100 over 46 records in the last 180 days details

References

3 references

URL	Tags
https://xenbits.xenproject.org/xsa/advisory-480.html
http://www.openwall.com/lists/oss-security/2026/03/17/6
http://xenbits.xen.org/xsa/advisory-480.html

Impacted products

1 product

Vendor	Product	Version
Xen	Xen	Unknown: consult Xen advisory XSA-480

Date Public

2026-03-17 12:00

Credits

This issue was discovered by Roger Pau Monné of XenServer.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-03-23T07:32:25.539Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/03/17/6"
          },
          {
            "url": "http://xenbits.xen.org/xsa/advisory-480.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-2026-23554",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-23T14:18:54.774466Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-367",
                "description": "CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-23T14:19:27.752Z",
          "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-480"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "value": "Xen 4.17 and onwards are vulnerable.  Xen 4.16 and older are not vulnerable.\n\nOnly x86 Intel systems with EPT support are vulnerable.\n\nOnly x86 HVM/PVH guests using HAP can leverage the vulnerability on affected\nsystems."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Roger Pau Monn\u00e9 of XenServer."
        }
      ],
      "datePublic": "2026-03-17T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "The Intel EPT paging code uses an optimization to defer flushing of any cached\nEPT state until the p2m lock is dropped, so that multiple modifications done\nunder the same locked region only issue a single flush.\n\nFreeing of paging structures however is not deferred until the flushing is\ndone, and can result in freed pages transiently being present in cached state.\nSuch stale entries can point to memory ranges not owned by the guest, thus\nallowing access to unintended memory regions."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "Privilege escalation, Denial of Service (DoS) affecting the entire host,\nand information leaks."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-23T06:56:52.344Z",
        "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "shortName": "XEN"
      },
      "references": [
        {
          "url": "https://xenbits.xenproject.org/xsa/advisory-480.html"
        }
      ],
      "title": "Use after free of paging structures in EPT",
      "workarounds": [
        {
          "lang": "en",
          "value": "There are no mitigations."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
    "assignerShortName": "XEN",
    "cveId": "CVE-2026-23554",
    "datePublished": "2026-03-23T06:56:52.344Z",
    "dateReserved": "2026-01-14T13:07:36.961Z",
    "dateUpdated": "2026-03-23T14:19:27.752Z",
    "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.

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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.
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