CVE-2025-65838: PublicCMS Path Traversal Vulnerability

CVE-2025-65838 Overview

CVE-2025-65838 is a high-severity path traversal vulnerability discovered in PublicCMS V5.202506.b. The vulnerability exists in the doUploadSitefile method, which fails to properly sanitize user-supplied file path input. This allows unauthenticated remote attackers to traverse directory structures and access sensitive files outside the intended web root directory.

Path traversal vulnerabilities (CWE-22) occur when software constructs a pathname using user input without adequate neutralization of special elements such as "../" sequences. In this case, attackers can exploit the file upload functionality to read arbitrary files from the server, potentially exposing configuration files, credentials, and other sensitive data.

Critical Impact

Unauthenticated attackers can remotely access sensitive files on affected PublicCMS servers, potentially leading to information disclosure and further system compromise.

Affected Products

• PublicCMS V5.202506.b
• PublicCMS (cpe:2.3:a:publiccms:publiccms:5.202506.b:*:*:*:*:*:*:*)

Discovery Timeline

• 2025-12-01 - CVE-2025-65838 published to NVD
• 2025-12-04 - Last updated in NVD database

Technical Details for CVE-2025-65838

Vulnerability Analysis

The vulnerability resides in the doUploadSitefile method within PublicCMS V5.202506.b. This method is responsible for handling site file upload operations but contains insufficient input validation for file path parameters.

CVSS v3.1 Score: 7.5 (HIGH)

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

The CVSS vector breakdown indicates:

• Attack Vector (AV:N): Network-accessible, exploitable remotely
• Attack Complexity (AC:L): Low complexity, no specialized conditions required
• Privileges Required (PR:N): No authentication needed
• User Interaction (UI:N): No user interaction required
• Scope (S:U): Unchanged, impact limited to vulnerable component
• Confidentiality Impact (C:H): High confidentiality impact
• Integrity Impact (I:N): No integrity impact
• Availability Impact (A:N): No availability impact

EPSS Score: 0.047% probability of exploitation (14.7th percentile as of 2025-12-16)

Root Cause

The root cause of CVE-2025-65838 is improper input validation in the file path handling logic. The doUploadSitefile method accepts user-controlled input for file paths without properly sanitizing directory traversal sequences such as ../ or encoded variants. This allows attackers to escape the intended directory context and access files anywhere on the filesystem that the web application has read permissions for.

The vulnerability falls under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), a common weakness where software fails to properly neutralize special characters in pathname construction.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can craft malicious HTTP requests to the vulnerable doUploadSitefile endpoint with path traversal sequences embedded in the file path parameter.

The exploitation flow involves:

1. Attacker identifies a PublicCMS instance running version V5.202506.b
2. Attacker crafts a malicious request targeting the doUploadSitefile endpoint
3. The request includes path traversal sequences (e.g., ../../../etc/passwd) in the file path parameter
4. The server processes the request without proper sanitization
5. Sensitive files outside the web root are accessed and returned to the attacker

Technical details and proof-of-concept information can be found in the external references, including the GitHub issue tracker at https://github.com/sanluan/PublicCMS/issues/101 and the detailed vulnerability write-up at https://github.com/Hyperkopite/PublicCMS_Vulns/blob/main/RCE_1.md.

Detection Methods for CVE-2025-65838

Indicators of Compromise

• HTTP requests containing path traversal sequences (../, ..%2f, %2e%2e/) targeting file upload endpoints
• Unusual access patterns to the doUploadSitefile method or related upload controllers
• Web server logs showing requests with encoded directory traversal characters
• Access to sensitive configuration files from unexpected sources
• Anomalous file read operations on system files like /etc/passwd, configuration files, or database credentials

Detection Strategies

Web Application Firewall (WAF) Rules:
Configure WAF rules to detect and block requests containing path traversal patterns. Look for sequences like ../, ..\\, URL-encoded variants (%2e%2e%2f), and double-encoded variants.

Log Analysis:
Monitor web server access logs for suspicious patterns in file upload requests. Implement alerting for requests containing traversal sequences or attempts to access files outside the web root.

Network Traffic Monitoring:
Deploy network intrusion detection systems (NIDS) to identify path traversal attempts in HTTP traffic. SentinelOne Singularity platform provides behavioral analysis that can detect anomalous file access patterns indicative of path traversal exploitation.

File Integrity Monitoring:
Monitor for unexpected file access events, particularly to sensitive configuration files and credential stores.

Monitoring Recommendations

Organizations running PublicCMS should implement comprehensive monitoring:

1. Enable detailed access logging for all web application endpoints
2. Configure real-time alerting for path traversal patterns in request parameters
3. Monitor file system access events for the web application service account
4. Deploy endpoint detection and response (EDR) solutions like SentinelOne to detect post-exploitation activities
5. Regularly review authentication logs for anomalous access patterns following potential exploitation

How to Mitigate CVE-2025-65838

Immediate Actions Required

• Identify all PublicCMS instances running version V5.202506.b in your environment
• Implement network segmentation to limit access to vulnerable PublicCMS servers
• Deploy WAF rules to block path traversal attempts targeting file upload endpoints
• Review server access logs for indicators of prior exploitation
• Consider taking vulnerable instances offline until a patch is applied

Patch Information

As of the last NVD update on 2025-12-04, administrators should check the official PublicCMS GitHub repository at https://github.com/sanluan/PublicCMS for security updates and patches addressing this vulnerability. Monitor the vendor's release channels for updated versions that remediate the path traversal issue in the doUploadSitefile method.

When a patch becomes available:

1. Test the update in a staging environment before production deployment
2. Create a backup of the existing installation
3. Apply the security update following vendor guidelines
4. Verify the fix by testing for path traversal vulnerabilities

Workarounds

If an immediate patch is not available, implement the following compensating controls:

Network-Level Controls:
Restrict network access to the PublicCMS application to trusted IP ranges only. Use firewall rules to limit exposure of the vulnerable endpoint.

Web Application Firewall:
Deploy or configure a WAF with rules to sanitize and block requests containing path traversal sequences:

# Example ModSecurity rule to block path traversal attempts
SecRule REQUEST_URI|ARGS|ARGS_NAMES "@rx (\.\./|\.\.\\)" \
    "id:1001,phase:2,deny,status:403,msg:'Path Traversal Attempt Blocked'"

Application-Level Hardening:
If possible, implement input validation at the application level by modifying the doUploadSitefile method to sanitize file paths and restrict access to the intended directory only. Ensure the web application runs with minimal filesystem permissions.

Monitoring and Response:
Deploy SentinelOne Singularity platform for real-time threat detection and response capabilities. The platform's behavioral AI can identify exploitation attempts and automatically respond to contain threats before data exfiltration occurs.