S4E just found a high top 10 tcp port service scan
critical·Misconfiguration·Updated Oct 8, 2025

CVE-2021-27856 Scanner

CVE-2021-27856 Scanner - Unauthorized Admin Access vulnerability in FatPipe WARP/IPVPN/MPVPN

Est. Time~10 seconds
Scan TypeSingle Scan
Targetsdomain, subdomain, ipv4
CostFree
0
Times Used
by S4E users
0
Assets Scanned
domains & IPs
0
Vulnerabilities Found
confirmed findings
References
CVECVE-2021-27856
9.8
CVSScritical
Exploitable remotely over the internet · no authentication required.

FatPipe WARP, IPVPN, and MPVPN software prior to versions 10.1.2r60p91 and 10.2.2r42 includes an account named "cmuser" that has administrative privileges and no password. Older versions of FatPipe software may also be vulnerable. The FatPipe advisory identifier for this vulnerability is FPSA002.

Attack Vector
Network
Privileges Req.
None
User Interaction
None
Affected
WARPby FatPipe
AFFECTED< 10.1.2r60p91SAFE ✓≥ 10.1.2r60p91
IPVPNby FatPipe
AFFECTED< 10.1.2r60p91SAFE ✓≥ 10.1.2r60p91
MPVPNby FatPipe
AFFECTED< 10.1.2r60p91SAFE ✓≥ 10.1.2r60p91
Updated Aug 19, 2026View on NVD →
Detail

FatPipe WARP, IPVPN, and MPVPN are network appliances used to facilitate secure data transfer and improve connectivity over wide area networks (WANs). These products are often deployed by enterprises and organizations to enhance internet connectivity and ensure high availability, load balancing, and traffic optimization. The primary audience for these devices is network administrators and IT staff within organizations that require reliable and secure internet performance. The products are capable of supporting various routing protocols and are often used in situations where multiple internet connections are aggregated for improved bandwidth and reliability. They are particularly useful for ensuring business continuity by providing fallback and load-sharing options across different internet service providers.

The vulnerability within FatPipe WARP/IPVPN/MPVPN is classified as Unauthorized Admin Access. It is due to a backdoor account named "cmuser" with administrative privileges that lacks a password. This allows attackers to gain unauthorized access to the system without needing to bypass authentication mechanisms. The vulnerability is critically severe due to its potential for exploitation by attackers to gain full control over the affected devices. It impacts versions prior to 10.1.2r60p91 and 10.2.2r42, posing significant security risks if left unpatched.

The vulnerability can be exploited remotely without authentication by sending a specially crafted request to the login endpoint of the affected appliances. Specifically, the vulnerability lies in the login functionality where the backdoor account can be used to gain administrative privileges, which are executed through the HTTP POST method. The vulnerable endpoint is '/fpui/loginServlet,' and the attacker can exploit the issue by submitting a direct login request using the 'cmuser' account without a password. Exploitation results in unauthorized administrative access to the system.

If this vulnerability is exploited, an attacker could gain full administrative control over the appliance, leading to unauthorized configuration changes, data exfiltration, denial of service, or use of the device as a platform for launching further attacks on the network. It might also allow the attacker to escalate privileges, install malware, intercept or manipulate network traffic, and otherwise compromise the integrity, confidentiality, and availability of the affected systems and any connected resources.

REFERENCES

Solution Advice
  • Immediately update your FatPipe WARP/IPVPN/MPVPN software to versions 10.1.2r60p91 or 10.2.2r42 or later.
  • Conduct a thorough audit of all user accounts and remove or disable any unauthorized accounts.
  • Implement strong authentication mechanisms, such as multi-factor authentication, to enhance security.
  • Regularly monitor and review system logs for any unauthorized access attempts or unusual activity.
  • Apply network segmentation and firewall rules to limit exposure only to trusted networks and administrators.

Get AI-powered remediation steps tailored to your asset.

Try AI Solutions →

Check your infrastructure.
Right now.

11,000+ scanners. Free to start. No credit card required.