CVE-2021-40098 : Security Advisory and Response

Concrete CMS versions up to 8.5.5 are affected by a Path Traversal vulnerability that can lead to Remote Code Execution (RCE) through external forms.

Understanding CVE-2021-40098

Concrete CMS versions up to 8.5.5 are susceptible to a Path Traversal vulnerability that can be exploited for RCE using a regular expression in external forms.

What is CVE-2021-40098?

CVE-2021-40098 is a security vulnerability found in Concrete CMS versions up to 8.5.5, allowing attackers to execute remote code through external forms by manipulating regular expressions.

The Impact of CVE-2021-40098

Attackers can exploit this vulnerability to achieve RCE, potentially compromising the affected systems.

Technical Details of CVE-2021-40098

Concrete CMS through version 8.5.5 is affected by this vulnerability.

Vulnerability Description

An issue in Concrete CMS allows a Path Traversal attack leading to RCE by inserting a regular expression in an external form.

Affected Systems and Versions

Product: Concrete CMS
Vendor: N/A
Versions: Up to 8.5.5
Status: Affected

Exploitation Mechanism

Attackers can exploit this vulnerability by adding a crafted regular expression in external forms of Concrete CMS.

Mitigation and Prevention

It is crucial to take immediate steps to secure the environment and prevent exploitation.

Immediate Steps to Take

Update Concrete CMS to version 8.5.6 or newer to patch the vulnerability.
Monitor and review external form submissions for any suspicious patterns.
Restrict access to external forms where possible to trusted users only.

Long-Term Security Practices

Regularly update and patch software to protect against known vulnerabilities.
Implement strict access controls and validate user inputs to prevent injection attacks.

Patching and Updates

Concrete CMS users should update to version 8.5.6 to mitigate the vulnerability and enhance system security.