CVE-2025-40841: Ericsson Indoor Connect 8855 CSRF Flaw

CVE-2025-40841 Overview

CVE-2025-40841 is a Cross-Site Request Forgery (CSRF) vulnerability affecting Ericsson Indoor Connect 8855 versions prior to 2025.Q3. This vulnerability allows attackers to trick authenticated users into performing unintended actions on the affected system, potentially leading to unauthorized modification of certain information without the user's knowledge or consent.

Critical Impact

Attackers can exploit this CSRF vulnerability to perform unauthorized modifications to system configurations or data by leveraging an authenticated user's session, potentially compromising the integrity of the Indoor Connect deployment.

Affected Products

• Ericsson Indoor Connect 8855 versions prior to 2025.Q3

Discovery Timeline

• 2026-03-25 - CVE CVE-2025-40841 published to NVD
• 2026-03-25 - Last updated in NVD database

Technical Details for CVE-2025-40841

Vulnerability Analysis

This vulnerability is classified under CWE-352 (Cross-Site Request Forgery). CSRF attacks exploit the trust that a web application has in the user's browser. When a user is authenticated to the Ericsson Indoor Connect 8855 management interface, their browser automatically includes authentication credentials (such as session cookies) with every request to the application.

The vulnerability exists because the affected versions lack proper anti-CSRF protections, such as CSRF tokens or same-site cookie attributes. This allows an attacker to craft malicious requests that, when executed by an authenticated user's browser, will be treated as legitimate by the application.

Root Cause

The root cause of this vulnerability is the absence of adequate CSRF protection mechanisms in the Ericsson Indoor Connect 8855 web interface. The application fails to implement proper request validation to ensure that state-changing requests originate from the legitimate application interface rather than a malicious third-party site. Without CSRF tokens or other verification mechanisms, the server cannot distinguish between legitimate user-initiated requests and forged requests initiated by an attacker.

Attack Vector

The attack vector for this vulnerability is network-based and requires user interaction. An attacker would need to:

1. Craft a malicious web page or email containing a forged request targeting the Ericsson Indoor Connect 8855 management interface
2. Trick an authenticated administrator or user into visiting the malicious page or clicking a malicious link
3. When the victim's browser loads the malicious content, it automatically sends the forged request to the vulnerable application
4. The application processes the request as legitimate because the victim's valid session credentials are automatically included

The exploitation requires that the victim be authenticated to the Indoor Connect management interface at the time they interact with the attacker's malicious content. For detailed technical information, refer to the Ericsson CVE-2025-40841 Advisory.

Detection Methods for CVE-2025-40841

Indicators of Compromise

• Unexpected configuration changes in the Ericsson Indoor Connect 8855 system that cannot be attributed to authorized administrative actions
• Audit logs showing administrative actions performed at unusual times or from unexpected source IP addresses
• User reports of clicking links or visiting websites immediately before noticing unauthorized changes

Detection Strategies

• Monitor web server access logs for patterns indicative of CSRF attacks, such as state-changing requests with unusual Referer headers or missing Origin headers
• Implement network monitoring to detect requests to the Indoor Connect management interface originating from external referrer domains
• Review audit logs for administrative actions that do not correlate with known maintenance windows or authorized user activity

Monitoring Recommendations

• Enable comprehensive logging on the Ericsson Indoor Connect 8855 management interface to capture all administrative actions with timestamps and source information
• Configure alerts for configuration changes to critical system settings
• Implement Security Information and Event Management (SIEM) rules to correlate management interface access patterns with potential CSRF attack indicators

How to Mitigate CVE-2025-40841

Immediate Actions Required

• Upgrade Ericsson Indoor Connect 8855 to version 2025.Q3 or later, which addresses this vulnerability
• Restrict network access to the management interface to trusted networks and IP addresses only
• Ensure administrators log out of the management interface when not actively in use
• Educate users with management access about the risks of clicking unknown links while authenticated to administrative interfaces

Patch Information

Ericsson has released version 2025.Q3 of the Indoor Connect 8855 firmware which addresses this CSRF vulnerability. Organizations should prioritize upgrading to this patched version as soon as possible. For detailed patch information and download instructions, consult the Ericsson March 2026 Security Bulletin.

Workarounds

• Implement network segmentation to isolate the Indoor Connect management interface from general user networks and the internet
• Configure firewall rules to restrict access to the management interface to specific administrative workstations or jump hosts
• Use a dedicated browser or browser profile exclusively for administrative tasks, keeping it separate from general web browsing
• Consider implementing a web application firewall (WAF) with CSRF protection rules in front of the management interface as an additional defense layer

# Example firewall configuration to restrict management interface access
# Restrict management interface (example port 443) to admin network only
iptables -A INPUT -p tcp --dport 443 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP