Vulnerability-Lookup

GHSA-2PHQ-CM26-22PM

Vulnerability from github – Published: 2026-09-09 18:32 – Updated: 2026-09-09 18:32

Details

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.

Severity

8.1 (High)


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

9.2 (Critical)


                  
                    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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-87930"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-502"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-09T17:17:53Z",
    "severity": "CRITICAL"
  },
  "details": "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": "GHSA-2phq-cm26-22pm",
  "modified": "2026-09-09T18:32:05Z",
  "published": "2026-09-09T18:32:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87930"
    },
    {
      "type": "WEB",
      "url": "https://github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md"
    },
    {
      "type": "WEB",
      "url": "https://github.com/EviL0rd/maxsite-cve6/blob/main/2026.09.08-maxsite-cms-unsafe-unserialize-object-injection.md"
    },
    {
      "type": "WEB",
      "url": "https://github.com/maxsite/cms"
    },
    {
      "type": "WEB",
      "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254"
    },
    {
      "type": "WEB",
      "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L670-L680"
    },
    {
      "type": "WEB",
      "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L740-L742"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/maxsite-cms-through-109.6-php-object-injection-via-ci-session"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-87930 (GCVE-0-2026-87930)

Vulnerability from cvelistv5 – Published: 2026-09-09 16:45 – Updated: 2026-09-24 14:21 X_Open Source Unsupported When Assigned

Title

MaxSite CMS through 109.6 PHP Object Injection via ci_session

Summary

Severity

9.2 (Critical)


                        
                          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

8.1 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-09 17:22 UTC

CWE

CWE-502 - Deserialization of Untrusted Data

Assigner

VulnCheck CNA under the mitre root

CNA scorecard B 84/100 over 7156 records in the last 180 days details

References

7 references

URL	Tags
https://github.com/maxsite/cms	product
https://github.com/EviL0rd/maxsite-cve6/blob/main…	exploittechnical-description
https://github.com/maxsite/cms/blob/2ca0a0c7d1d71…	technical-description
https://github.com/maxsite/cms/blob/2ca0a0c7d1d71…	technical-description
https://github.com/EviL0rd/maxsite-cve4/blob/main…	technical-description
https://github.com/maxsite/cms/blob/2ca0a0c7d1d71…	technical-description
https://www.vulncheck.com/advisories/maxsite-cms-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
MaxSite	MaxSite CMS	Affected: 0.78 , ≤ 109.6 (custom) cpe:2.3:a:max-3000:maxsite_cms::::::::

Date Public

2026-09-09 00:00

Credits

EVIL0RD

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-87930",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-09T17:22:33.214701Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-09T17:24:57.540Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:max-3000:maxsite_cms:*:*:*:*:*:*:*:*",
                  "versionEndIncluding": "109.6",
                  "versionStartIncluding": "0.78",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "EVIL0RD"
        }
      ],
      "datePublic": "2026-09-09T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
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        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        },
        {
          "cvssV3_1": {
            "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",
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          }
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      "providerMetadata": {
        "dateUpdated": "2026-09-24T14:21:32.195Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
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      },
      "references": [
        {
          "tags": [
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          "url": "https://github.com/maxsite/cms"
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        {
          "tags": [
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          "url": "https://github.com/EviL0rd/maxsite-cve6/blob/main/2026.09.08-maxsite-cms-unsafe-unserialize-object-injection.md"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L670-L680"
        },
        {
          "tags": [
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          "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L740-L742"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md"
        },
        {
          "tags": [
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          "url": "https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254"
        },
        {
          "name": "VulnCheck Advisory: MaxSite CMS through 109.6 PHP Object Injection via ci_session",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/maxsite-cms-through-109.6-php-object-injection-via-ci-session"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "tags": [
        "x_open-source",
        "unsupported-when-assigned"
      ],
      "title": "MaxSite CMS through 109.6 PHP Object Injection via ci_session",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-87930",
    "datePublished": "2026-09-09T16:45:00.798Z",
    "dateReserved": "2026-09-09T16:12:38.084Z",
    "dateUpdated": "2026-09-24T14:21:32.195Z",
    "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.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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