CVE-2026-70554
MaxSite CMS Unauthenticated PHP Object Injection via maxsite_comuser Cookie
Description
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.
INFO
Published Date :
Aug. 4, 2026, 9:16 p.m.
Last Modified :
Oct. 24, 2026, 3:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 3.1 | CRITICAL | MITRE-CVE | ||||
| CVSS 4.0 | CRITICAL | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Avoid unserializing untrusted data.
- Use safe alternatives to unserialize().
- Implement strict input validation.
- Update to a secure version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-70554.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-70554 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-70554
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-70554 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-70554 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Changed Translation Title: MaxSite CMS de MaxSite, Description: MaxSite CMS contiene una vulnerabilidad de inyección de objetos PHP que permite a atacantes no autenticados ejecutar código arbitrario al pasar datos serializados controlados por el atacante en la cookie maxsite_comuser directamente a unserialize() sin validación o lista blanca de clases. Los atacantes pueden crear una carga útil de objeto PHP serializado malicioso entregada en una única solicitud HTTP para activar métodos mágicos durante la reconstrucción del grafo de objetos, lo que permite ataques de programación orientada a propiedades o ejecución remota de código a través de cadenas de gadgets disponibles, como las que apuntan a las extensiones SoapClient o Imagick. Title: MaxSite CMS de MaxSite, Description: MaxSite CMS contiene una vulnerabilidad de inyección de objetos PHP que permite a atacantes no autenticados ejecutar código arbitrario al pasar datos serializados controlados por el atacante en la cookie maxsite_comuser directamente a unserialize() sin validación o lista blanca de clases. Los atacantes pueden crear una carga útil de objeto PHP serializado malicioso entregada en una única solicitud HTTP para activar métodos mágicos durante la reconstrucción del grafo de objetos, lo que permite ataques de programación orientada a propiedades o ejecución remota de código a través de cadenas de gadgets disponibles, como las que apuntan a las extensiones SoapClient o Imagick. -
CVE Translated by [email protected]
Oct. 23, 2026
Action Type Old Value New Value Added Translation Title: MaxSite CMS de MaxSite, Description: MaxSite CMS contiene una vulnerabilidad de inyección de objetos PHP que permite a atacantes no autenticados ejecutar código arbitrario al pasar datos serializados controlados por el atacante en la cookie maxsite_comuser directamente a unserialize() sin validación o lista blanca de clases. Los atacantes pueden crear una carga útil de objeto PHP serializado malicioso entregada en una única solicitud HTTP para activar métodos mágicos durante la reconstrucción del grafo de objetos, lo que permite ataques de programación orientada a propiedades o ejecución remota de código a través de cadenas de gadgets disponibles, como las que apuntan a las extensiones SoapClient o Imagick. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 05, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-70554', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-05T13:52:48.956931Z'} -
New CVE Received by [email protected]
Aug. 04, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'MaxSite', 'product': 'MaxSite CMS', 'versions': [{'status': 'affected', 'version': '0.78', 'versionType': 'custom', 'lessThanOrEqual': '109.5'}, {'status': 'unaffected', 'version': '109.6', 'versionType': 'custom'}], 'defaultStatus': 'affected'}] Added Description 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. Added CVSS V4.0 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 Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-502 Added Reference https://github.com/maxsite/cms Added Reference https://max-3000.com/page/maxsite-cms-109-6 Added Reference https://www.vulncheck.com/advisories/maxsite-cms-unauthenticated-php-object-injection-via-maxsite-comuser-cookie