CVE-2026-7888
Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components that lack the allowed_classes restriction.
Description
Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components that lack the allowed_classes restriction. An unauthenticated attacker may trigger arbitrary PHP object instantiation if a malicious serialized payload has been placed in the database. Thanks XananasX7 and Sanjorn Keeratirungsan (dizconnect) for both independently reporting. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 8.4 with vector CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N.
INFO
Published Date :
June 3, 2026, 7:16 p.m.
Last Modified :
July 22, 2026, 8:10 p.m.
Remotely Exploit :
No
Source :
ff5b8ace-8b95-4078-9743-eac1ca5451de
Affected Products
The following products are affected by CVE-2026-7888
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | HIGH | ff5b8ace-8b95-4078-9743-eac1ca5451de | ||||
| CVSS 4.0 | HIGH | ff5b8ace-8b95-4078-9743-eac1ca5451de |
Solution
- Update Concrete CMS to 9.5.2 or later.
- Review and sanitize all user-supplied input.
- Restrict unserialize() usage with allowed_classes.
- Monitor database for malicious serialized payloads.
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-2026-7888.
| URL | Resource |
|---|---|
| https://documentation.concretecms.org/9-x/developers/introduction/version-history/952-release-notes |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-7888 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-2026-7888
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-2026-7888 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-7888 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]
Jul. 22, 2026
Action Type Old Value New Value Added Translation Title: Concrete CMS, Description: Concrete CMS anterior a 9.5.2 es vulnerable a la Inyección de objetos PHP a través de llamadas a unserialize() en los componentes Workflow, Form block y File/Set que carecen de la restricción allowed_classes. Un atacante no autenticado puede desencadenar la instanciación arbitraria de objetos PHP si se ha colocado una carga útil serializada maliciosa en la base de datos. Gracias a XananasX7 y Sanjorn Keeratirungsan (dizconnect) por informar ambos de forma independiente. El equipo de seguridad de Concrete CMS otorgó a esta vulnerabilidad una puntuación CVSS v.4.0 de 8.4 con el vector CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. -
CVE Modified by ff5b8ace-8b95-4078-9743-eac1ca5451de
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/concretecms/concretecms', 'vendor': 'Concrete CMS', 'product': 'Concrete CMS', 'versions': [{'status': 'affected', 'version': '5.0', 'lessThan': '9.5.2', 'versionType': 'git'}], 'collectionURL': 'https://github.com/concretecms/concretecms', 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-7888', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-03T19:07:44.886735Z'} -
New CVE Received by ff5b8ace-8b95-4078-9743-eac1ca5451de
Jun. 03, 2026
Action Type Old Value New Value Added Description Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components that lack the allowed_classes restriction. An unauthenticated attacker may trigger arbitrary PHP object instantiation if a malicious serialized payload has been placed in the database. Thanks XananasX7 and Sanjorn Keeratirungsan (dizconnect) for both independently reporting. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 8.4 with vector CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:H/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 CWE CWE-502 Added Reference https://documentation.concretecms.org/9-x/developers/introduction/version-history/952-release-notes