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FKIE_CVE-2026-87930

Vulnerability from fkie_nvd - Published: 2026-09-09 17:17 - Updated: 2026-09-09 20:14
Severity
8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
MaxSite CMS through 109.6 passes the ci_session cookie to unserialize() without class restrictions, allowing unauthenticated attackers to inject PHP objects. Attackers can forge valid session cookies using the hardcoded encryption key to trigger magic methods and corrupt application state or achieve code execution if gadget classes exist.
References
disclosure@vulncheck.comhttps://github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md
disclosure@vulncheck.comhttps://github.com/EviL0rd/maxsite-cve6/blob/main/2026.09.08-maxsite-cms-unsafe-unserialize-object-injection.md
disclosure@vulncheck.comhttps://github.com/maxsite/cms
disclosure@vulncheck.comhttps://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254
disclosure@vulncheck.comhttps://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L670-L680
disclosure@vulncheck.comhttps://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L740-L742
disclosure@vulncheck.comhttps://www.vulncheck.com/advisories/maxsite-cms-through-109.6-php-object-injection-via-ci-session
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:github/maxsite/cms",
          "product": "MaxSite CMS",
          "repo": "https://github.com/maxsite/cms",
          "vendor": "MaxSite",
          "versions": [
            {
              "lessThanOrEqual": "109.6",
              "status": "affected",
              "version": "0.78",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "disclosure@vulncheck.com"
    }
  ],
  "cveTags": [
    {
      "sourceIdentifier": "disclosure@vulncheck.com",
      "tags": [
        "unsupported-when-assigned"
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "MaxSite CMS through 109.6 passes the ci_session cookie to unserialize() without class restrictions, allowing unauthenticated attackers to inject PHP objects. Attackers can forge valid session cookies using the hardcoded encryption key to trigger magic methods and corrupt application state or achieve code execution if gadget classes exist."
    }
  ],
  "id": "CVE-2026-87930",
  "lastModified": "2026-09-09T20:14:00.420",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 5.9,
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 9.2,
          "baseSeverity": "CRITICAL",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-87930",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-09T17:22:33.214701Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-09T17:17:53.990",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/EviL0rd/maxsite-cve6/blob/main/2026.09.08-maxsite-cms-unsafe-unserialize-object-injection.md"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/maxsite/cms"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L670-L680"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L740-L742"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/maxsite-cms-through-109.6-php-object-injection-via-ci-session"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-502"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}



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