Vulnerability-Lookup

CERTFR-2025-AVI-0556

Vulnerability from certfr_avis - Published: 2025-07-03 - Updated: 2025-07-03

Une vulnérabilité a été découverte dans Citrix XenServer. Elle permet à un attaquant de provoquer un déni de service à distance.

Solutions

Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation).

L’éditeur indique que le produit Hypervisor en version 8.2 CU1 est en fin de vie et ne bénéficie plus de mises à jour de sécurité.

Impacted products

	Vendor	Product	Description
	Citrix	XenServer	XenServer 8.4 sans le dernier correctif de sécurité

References

Title

Publication Time

CVE-2025-27465 (GCVE-0-2025-27465)

Vulnerability from cvelistv5 – Published: 2025-07-16 09:08 – Updated: 2025-11-04 21:09

Title

x86: Incorrect stubs exception handling for flags recovery

Summary

Certain instructions need intercepting and emulating by Xen. In some cases Xen emulates the instruction by replaying it, using an executable stub. Some instructions may raise an exception, which is supposed to be handled gracefully. Certain replayed instructions have additional logic to set up and recover the changes to the arithmetic flags. For replayed instructions where the flags recovery logic is used, the metadata for exception handling was incorrect, preventing Xen from handling the the exception gracefully, treating it as fatal instead.

Severity

4.3 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-07-16 20:46 UTC

CWE

CWE-755 - Improper Handling of Exceptional Conditions

Assigner

XEN CNA under the mitre root

CNA scorecard D 56/100 over 48 records in the last 180 days details

References

3 references

URL	Tags
https://xenbits.xenproject.org/xsa/advisory-470.html
http://xenbits.xen.org/xsa/advisory-470.html
http://www.openwall.com/lists/oss-security/2025/07/01/1

Impacted products

1 product

Vendor	Product	Version
Xen	Xen	Unknown: consult Xen advisory XSA-470

Date Public

2025-07-01 11:56

Credits

This issue was discovered by Andrew Cooper of XenServer.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "LOW",
              "baseScore": 4.3,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2025-27465",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-07-16T20:46:06.289437Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-755",
                "description": "CWE-755 Improper Handling of Exceptional Conditions",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-07-17T15:00:57.741Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-04T21:09:50.127Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://xenbits.xen.org/xsa/advisory-470.html"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2025/07/01/1"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Xen",
          "vendor": "Xen",
          "versions": [
            {
              "status": "unknown",
              "version": "consult Xen advisory XSA-470"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "value": "Xen 4.9 and onwards are vulnerable.  Xen 4.8 and older are not\nvulnerable.\n\nOnly x86 systems are vulnerable.  ARM systems are not vulnerable.\n\nOnly HVM or PVH guests can leverage the vulnerability.  PV guests cannot\nleverage the vulnerability."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Andrew Cooper of XenServer."
        }
      ],
      "datePublic": "2025-07-01T11:56:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Certain instructions need intercepting and emulating by Xen.  In some\ncases Xen emulates the instruction by replaying it, using an executable\nstub.  Some instructions may raise an exception, which is supposed to be\nhandled gracefully.  Certain replayed instructions have additional logic\nto set up and recover the changes to the arithmetic flags.\n\nFor replayed instructions where the flags recovery logic is used, the\nmetadata for exception handling was incorrect, preventing Xen from\nhandling the the exception gracefully, treating it as fatal instead."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "An unprivileged guest can cause a hypervisor crash, causing a Denial of\nService (DoS) of the entire host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-07-16T09:08:39.931Z",
        "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "shortName": "XEN"
      },
      "references": [
        {
          "url": "https://xenbits.xenproject.org/xsa/advisory-470.html"
        }
      ],
      "title": "x86: Incorrect stubs exception handling for flags recovery",
      "workarounds": [
        {
          "lang": "en",
          "value": "There are no mitigations."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
    "assignerShortName": "XEN",
    "cveId": "CVE-2025-27465",
    "datePublished": "2025-07-16T09:08:39.931Z",
    "dateReserved": "2025-02-26T09:16:54.461Z",
    "dateUpdated": "2025-11-04T21:09:50.127Z",
    "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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