CVE-2026-45078

{
  "id": "CVE-2026-45078",
  "sourceIdentifier": "[email protected]",
  "published": "2026-05-28T17:16:31.750",
  "lastModified": "2026-10-26T13:10:00.140",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1."
    },
    {
      "lang": "es",
      "value": "Synapse es una implementación de homeserver de Matrix de código abierto. Antes de 1.152.1, los usuarios locales autenticados pueden hacer que Synapse prive a otras solicitudes de CPU y provoque que otras solicitudes fallen, causando que a otros usuarios se les deniegue el servicio. Esta vulnerabilidad está corregida en 1.152.1."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "element-hq",
          "product": "synapse",
          "versions": [
            {
              "version": "< 1.152.1",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-05-29T15:31:35.828810Z",
          "id": "CVE-2026-45078",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:element:synapse:*:*:*:*:*:*:*:*",
              "versionEndExcluding": "1.152.1",
              "matchCriteriaId": "30470335-8DE4-4DE9-84B0-09D11E4A2D70"
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  ],
  "references": [
    {
      "url": "https://github.com/element-hq/synapse/security/advisories/GHSA-8q93-326v-3m7g",
      "source": "[email protected]",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ]
    }
  ]
}