CVE-2026-23557 (GCVE-0-2026-23557)
Vulnerability from cvelistv5
Published
2026-05-19 12:49
Modified
2026-05-19 14:42
Severity ?
6.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Summary
Any guest can cause xenstored to crash by issuing a XS_RESET_WATCHES command within a transaction due to an assert() triggering. In case xenstored was built with NDEBUG #defined nothing bad will happen, as assert() is doing nothing in this case. Note that the default is not to define NDEBUG for xenstored builds even in release builds of Xen.
References
Impacted products
Vendor Product Version
Xen Xen Create a notification for this product.
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  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-05-19T13:06:41.611Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/04/28/11"
          },
          {
            "url": "http://xenbits.xen.org/xsa/advisory-484.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 6.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "CHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
              "version": "3.1"
            }
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          {
            "other": {
              "content": {
                "id": "CVE-2026-23557",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-19T14:42:12.994792Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
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        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-617",
                "description": "CWE-617 Reachable Assertion",
                "lang": "en",
                "type": "CWE"
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            ]
          }
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        "providerMetadata": {
          "dateUpdated": "2026-05-19T14:42:45.464Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Xen",
          "vendor": "Xen",
          "versions": [
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              "status": "unknown",
              "version": "consult Xen advisory XSA-484"
            }
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        }
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      "configurations": [
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          "lang": "en",
          "value": "All Xen systems from Xen 4.2 onwards are vulnerable. Systems up to\nXen 4.1 are not vulnerable.\n\nSystems using the C variant of xenstored or xenstore-stubdom built\nwithout NDEBUG are vulnerable. Systems using the OCaml variant of\nXenstore (oxenstored), or the C variant (xenstored or xenstore-stubdom)\nbuilt with NDEBUG defined are not vulnerable."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Andrii Sultanov of Vates."
        }
      ],
      "datePublic": "2026-04-28T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Any guest can cause xenstored to crash by issuing a XS_RESET_WATCHES\ncommand within a transaction due to an assert() triggering.\n\nIn case xenstored was built with NDEBUG #defined nothing bad will\nhappen, as assert() is doing nothing in this case. Note that the\ndefault is not to define NDEBUG for xenstored builds even in release\nbuilds of Xen."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "Any unprivileged domain can cause xenstored to crash, causing a\nDoS (denial of service) for any Xenstore action. This will result\nin an inability to perform further domain administration on the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-19T12:49:42.202Z",
        "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "shortName": "XEN"
      },
      "references": [
        {
          "url": "https://xenbits.xenproject.org/xsa/advisory-484.html"
        }
      ],
      "title": "Xenstored DoS via XS_RESET_WATCHES command",
      "workarounds": [
        {
          "lang": "en",
          "value": "There is no known mitigation available."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
    "assignerShortName": "XEN",
    "cveId": "CVE-2026-23557",
    "datePublished": "2026-05-19T12:49:42.202Z",
    "dateReserved": "2026-01-14T13:07:36.961Z",
    "dateUpdated": "2026-05-19T14:42:45.464Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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