GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-42487 (GCVE-0-2026-42487)

Vulnerability from cvelistv5 – Published: 2026-06-18 13:46 – Updated: 2026-06-18 15:07
VLAI
Title
x86 HVM I/O port list traversal
Summary
HVM guest I/O port accesses are subject to either emulation or at least translation. Translations are managed by the device model (via XEN_DOMCTL_ioport_mapping), and hence the linked list used may changed at any time. Traversal of those lists (while handling guest I/O port accesses) therefore needs synchronizing with updates, which was missing so far.
Severity
7.9 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-18 14:35 UTC
CWE
  • CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Assigner
References
Impacted products
Vendor Product Version CPE status
Xen Xen Unknown: consult Xen advisory XSA-491
guessed Create a notification for this product.
Date Public
2026-06-09 12:00
Credits
This issue was discovered by Jan Beulich of SUSE.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.9,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "LOW",
              "integrityImpact": "LOW",
              "privilegesRequired": "LOW",
              "scope": "CHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-42487",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-18T14:35:06.701148Z",
                "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": "2026-06-18T14:35:11.262Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-06-18T15:07:31.335Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://xenbits.xen.org/xsa/advisory-491.html"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/06/09/11"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Xen",
          "vendor": "Xen",
          "versions": [
            {
              "status": "unknown",
              "version": "consult Xen advisory XSA-491"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "value": "All Xen versions from at least 3.2 onwards are vulnerable.  Earlier\nversions have not been inspected.\n\nOnly x86 systems are vulnerable.  Arm systems are not vulnerable.\n\nOnly entities controlling HVM guests can leverage the vulnerability.\nThese are device models running in either a stub domain or de-privileged\nin Dom0."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Jan Beulich of SUSE."
        }
      ],
      "datePublic": "2026-06-09T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "HVM guest I/O port accesses are subject to either emulation or at least\ntranslation.  Translations are managed by the device model (via\nXEN_DOMCTL_ioport_mapping), and hence the linked list used may changed\nat any time.  Traversal of those lists (while handling guest I/O port\naccesses) therefore needs synchronizing with updates, which was missing\nso far."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "A device model of a HVM guest can cause a hypervisor crash, causing a\nDenial of Service (DoS) of the entire host.  Privilege escalation and\ninformation leaks cannot be ruled out."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-18T13:46:53.459Z",
        "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "shortName": "XEN"
      },
      "references": [
        {
          "url": "https://xenbits.xenproject.org/xsa/advisory-491.html"
        }
      ],
      "title": "x86 HVM I/O port list traversal",
      "workarounds": [
        {
          "lang": "en",
          "value": "Running only PV or PVH guests will avoid the vulnerability.\n\n(Switching from a device model stub domain or a de-privileged device\nmodel to a fully privileged Dom0 device model does NOT mitigate this\nvulnerability.  Rather, it simply recategorises the vulnerability to\nhostile management code, regarding it \"as designed\"; thus it merely\nreclassifies these issues as \"not a bug\".  The security of a Xen system\nusing stub domains is still better than with a qemu-dm running as a Dom0\nprocess.  Users and vendors of stub qemu dm systems should not change\ntheir configuration to use a Dom0 qemu process.)"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
    "assignerShortName": "XEN",
    "cveId": "CVE-2026-42487",
    "datePublished": "2026-06-18T13:46:53.459Z",
    "dateReserved": "2026-04-27T14:20:24.138Z",
    "dateUpdated": "2026-06-18T15:07:31.335Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-42487",
      "date": "2026-09-15",
      "epss": "0.00095",
      "percentile": "0.00741"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-42487\",\"sourceIdentifier\":\"security@xen.org\",\"published\":\"2026-06-18T14:17:25.297\",\"lastModified\":\"2026-06-22T18:38:02.507\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"HVM guest I/O port accesses are subject to either emulation or at least\\ntranslation.  Translations are managed by the device model (via\\nXEN_DOMCTL_ioport_mapping), and hence the linked list used may changed\\nat any time.  Traversal of those lists (while handling guest I/O port\\naccesses) therefore needs synchronizing with updates, which was missing\\nso far.\"}],\"affected\":[{\"source\":\"security@xen.org\",\"affectedData\":[{\"vendor\":\"Xen\",\"product\":\"Xen\",\"defaultStatus\":\"unknown\",\"versions\":[{\"version\":\"consult Xen advisory XSA-491\",\"status\":\"unknown\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H\",\"baseScore\":7.9,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.0,\"impactScore\":5.3}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-06-18T14:35:06.701148Z\",\"id\":\"CVE-2026-42487\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-362\"}]}],\"references\":[{\"url\":\"https://xenbits.xenproject.org/xsa/advisory-491.html\",\"source\":\"security@xen.org\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/06/09/11\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"http://xenbits.xen.org/xsa/advisory-491.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}",
    "redhat_vex": {
      "current_release_date": "2026-08-17T17:51:47+00:00",
      "cve": "CVE-2026-42487",
      "id": "CVE-2026-42487",
      "initial_release_date": "2026-06-18T13:46:53.459000+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "xen: x86 HVM I/O port list traversal",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42487.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-31T13:41:43Z",
      "cve": "CVE-2026-42487",
      "id": "CVE-2026-42487",
      "initial_release_date": "2026-06-12T02:27:53Z",
      "product_status:known_affected": "480",
      "product_status:recommended": "127",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-42487",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-42487.json",
      "version": "9"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"http://xenbits.xen.org/xsa/advisory-491.html\"}, {\"url\": \"http://www.openwall.com/lists/oss-security/2026/06/09/11\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2026-06-18T15:07:31.335Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"CHANGED\", \"version\": \"3.1\", \"baseScore\": 7.9, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"LOW\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-42487\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-06-18T14:35:06.701148Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-362\", \"description\": \"CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-06-18T14:35:00.921Z\"}}], \"cna\": {\"title\": \"x86 HVM I/O port list traversal\", \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"This issue was discovered by Jan Beulich of SUSE.\"}], \"impacts\": [{\"descriptions\": [{\"lang\": \"en\", \"value\": \"A device model of a HVM guest can cause a hypervisor crash, causing a\\nDenial of Service (DoS) of the entire host.  Privilege escalation and\\ninformation leaks cannot be ruled out.\"}]}], \"affected\": [{\"vendor\": \"Xen\", \"product\": \"Xen\", \"versions\": [{\"status\": \"unknown\", \"version\": \"consult Xen advisory XSA-491\"}], \"defaultStatus\": \"unknown\"}], \"datePublic\": \"2026-06-09T12:00:00.000Z\", \"references\": [{\"url\": \"https://xenbits.xenproject.org/xsa/advisory-491.html\"}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"Running only PV or PVH guests will avoid the vulnerability.\\n\\n(Switching from a device model stub domain or a de-privileged device\\nmodel to a fully privileged Dom0 device model does NOT mitigate this\\nvulnerability.  Rather, it simply recategorises the vulnerability to\\nhostile management code, regarding it \\\"as designed\\\"; thus it merely\\nreclassifies these issues as \\\"not a bug\\\".  The security of a Xen system\\nusing stub domains is still better than with a qemu-dm running as a Dom0\\nprocess.  Users and vendors of stub qemu dm systems should not change\\ntheir configuration to use a Dom0 qemu process.)\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"HVM guest I/O port accesses are subject to either emulation or at least\\ntranslation.  Translations are managed by the device model (via\\nXEN_DOMCTL_ioport_mapping), and hence the linked list used may changed\\nat any time.  Traversal of those lists (while handling guest I/O port\\naccesses) therefore needs synchronizing with updates, which was missing\\nso far.\"}], \"configurations\": [{\"lang\": \"en\", \"value\": \"All Xen versions from at least 3.2 onwards are vulnerable.  Earlier\\nversions have not been inspected.\\n\\nOnly x86 systems are vulnerable.  Arm systems are not vulnerable.\\n\\nOnly entities controlling HVM guests can leverage the vulnerability.\\nThese are device models running in either a stub domain or de-privileged\\nin Dom0.\"}], \"providerMetadata\": {\"orgId\": \"23aa2041-22e1-471f-9209-9b7396fa234f\", \"shortName\": \"XEN\", \"dateUpdated\": \"2026-06-18T13:46:53.459Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-42487\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-06-18T15:07:31.335Z\", \"dateReserved\": \"2026-04-27T14:20:24.138Z\", \"assignerOrgId\": \"23aa2041-22e1-471f-9209-9b7396fa234f\", \"datePublished\": \"2026-06-18T13:46:53.459Z\", \"assignerShortName\": \"XEN\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.


Detection rules are retrieved from Rulezet.


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.