Vulnerability-Lookup

CVE-2026-70554 (GCVE-0-2026-70554)

Vulnerability from cvelistv5 – Published: 2026-08-04 20:11 – Updated: 2026-08-05 14:28

Title

MaxSite CMS Unauthenticated PHP Object Injection via maxsite_comuser Cookie

Summary

MaxSite CMS contains a PHP object injection vulnerability that allows unauthenticated attackers to execute arbitrary code by passing attacker-controlled serialized data in the maxsite_comuser cookie directly to unserialize() without validation or class allowlisting. Attackers can craft a malicious serialized PHP object payload delivered in a single HTTP request to trigger magic methods during object graph reconstruction, enabling property-oriented programming attacks or remote code execution via available gadget chains such as those targeting SoapClient or Imagick extensions.

Severity

9.3 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

9.8 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-502 - Deserialization of Untrusted Data

Assigner

VulnCheck

References

3 references

URL	Tags
https://github.com/maxsite/cms	product
https://max-3000.com/page/maxsite-cms-109-6	patch
https://www.vulncheck.com/advisories/maxsite-cms-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
MaxSite	MaxSite CMS	Affected: 0.78 , ≤ 109.5 (custom) Unaffected: 109.6 (custom)

Date Public

2026-08-04 00:00

Credits

Amir Aliu & Enrik Mustafa

Show details on NVD website

JSON

To clipboard

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                "id": "CVE-2026-70554",
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          "name": "Patch Commit",
          "tags": [
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      "source": {
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}

GHSA-JM66-348J-QVV2

Vulnerability from github – Published: 2026-08-04 21:30 – Updated: 2026-08-04 21:30

Details

Severity

9.8 (Critical)


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

9.3 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-70554"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-502"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-04T21:16:38Z",
    "severity": "CRITICAL"
  },
  "details": "MaxSite CMS contains a PHP object injection vulnerability that allows unauthenticated attackers to execute arbitrary code by passing attacker-controlled serialized data in the maxsite_comuser cookie directly to unserialize() without validation or class allowlisting. Attackers can craft a malicious serialized PHP object payload delivered in a single HTTP request to trigger magic methods during object graph reconstruction, enabling property-oriented programming attacks or remote code execution via available gadget chains such as those targeting SoapClient or Imagick extensions.",
  "id": "GHSA-jm66-348j-qvv2",
  "modified": "2026-08-04T21:30:31Z",
  "published": "2026-08-04T21:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-70554"
    },
    {
      "type": "WEB",
      "url": "https://github.com/maxsite/cms"
    },
    {
      "type": "WEB",
      "url": "https://max-3000.com/page/maxsite-cms-109-6"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/maxsite-cms-unauthenticated-php-object-injection-via-maxsite-comuser-cookie"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/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"
    }
  ]
}

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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

CVE-2026-70554 (GCVE-0-2026-70554)

GHSA-JM66-348J-QVV2

Tags

Sightings

Nomenclature