CVE-2025-30411: Acronis Cyber Protect Auth Bypass Flaw

CVE-2025-30411 Overview

CVE-2025-30411 is a critical authentication bypass vulnerability affecting Acronis Cyber Protect products. The flaw stems from improper authentication mechanisms (CWE-1390: Weak Authentication), which allows unauthorized attackers to access and manipulate sensitive data without proper credentials. This vulnerability affects both Linux and Windows deployments of the enterprise backup and security solution.

Critical Impact

This vulnerability enables unauthenticated remote attackers to disclose and manipulate sensitive data in Acronis Cyber Protect deployments, potentially compromising backup integrity and exposing confidential organizational information.

Affected Products

• Acronis Cyber Protect 16 (Linux, Windows) before build 39938
• Acronis Cyber Protect 15 (Linux, Windows) before build 41800

Discovery Timeline

• February 20, 2026 - CVE-2025-30411 published to NVD
• February 20, 2026 - Last updated in NVD database

Technical Details for CVE-2025-30411

Vulnerability Analysis

This vulnerability represents a fundamental weakness in the authentication subsystem of Acronis Cyber Protect. The improper authentication implementation allows network-based attackers to bypass security controls entirely, gaining unauthorized access to protected resources. The scope-changed nature of this vulnerability indicates that exploitation can affect resources beyond the vulnerable component itself, potentially compromising the entire backup infrastructure and any systems relying on it.

The vulnerability is network-accessible with no complexity barriers, requiring no privileges or user interaction to exploit. This makes it particularly dangerous in enterprise environments where Acronis Cyber Protect manages critical backup operations and sensitive organizational data.

Root Cause

The root cause is classified under CWE-1390 (Weak Authentication), indicating that the authentication mechanism does not adequately verify the identity of actors attempting to access protected functionality. This weakness allows attackers to circumvent identity verification entirely, treating unauthenticated requests as if they were legitimate.

Attack Vector

The attack vector is network-based, meaning any attacker with network access to an affected Acronis Cyber Protect instance can potentially exploit this vulnerability. The attack flow involves:

1. Attacker identifies an exposed Acronis Cyber Protect management interface
2. Attacker crafts requests that bypass the authentication mechanism
3. Without valid credentials, the attacker gains access to sensitive backup data
4. The attacker can both read confidential information and manipulate backup configurations or data

Due to the nature of this vulnerability involving improper authentication bypass, specific exploitation would target the authentication endpoints of the Acronis Cyber Protect web management interface. Attackers could potentially access backup catalogs, restore points, and configuration data without providing valid credentials.

For detailed technical information, refer to the Acronis Security Advisory SEC-8768.

Detection Methods for CVE-2025-30411

Indicators of Compromise

• Unexpected access to backup management interfaces from unauthorized IP addresses
• Anomalous API calls to Acronis Cyber Protect endpoints without corresponding authentication events
• Unauthorized modifications to backup configurations or schedules
• Data exfiltration patterns from backup storage locations

Detection Strategies

• Monitor authentication logs for access to protected resources without corresponding successful login events
• Implement network traffic analysis to detect unusual patterns accessing Acronis Cyber Protect services
• Deploy Web Application Firewall (WAF) rules to detect authentication bypass attempts
• Configure SIEM alerts for API access anomalies on Acronis management ports

Monitoring Recommendations

• Enable detailed audit logging on all Acronis Cyber Protect instances
• Monitor for unauthorized configuration changes to backup policies
• Implement network segmentation alerts for traffic crossing security boundaries to backup infrastructure
• Track file access patterns on backup storage for signs of unauthorized data retrieval

How to Mitigate CVE-2025-30411

Immediate Actions Required

• Update Acronis Cyber Protect 16 to build 39938 or later immediately
• Update Acronis Cyber Protect 15 to build 41800 or later immediately
• Restrict network access to Acronis Cyber Protect management interfaces to trusted networks only
• Review access logs for any signs of prior exploitation

Patch Information

Acronis has released security patches addressing this vulnerability. Organizations should apply the following minimum builds:

• Acronis Cyber Protect 16: Build 39938 or later
• Acronis Cyber Protect 15: Build 41800 or later

Refer to the Acronis Security Advisory SEC-8768 for official patch download links and detailed upgrade instructions.

Workarounds

• Implement network segmentation to isolate Acronis Cyber Protect management interfaces from untrusted networks
• Deploy a reverse proxy with additional authentication layers in front of the management interface
• Use firewall rules to restrict access to management ports from authorized IP addresses only
• Enable VPN requirements for all remote access to backup management infrastructure

# Example firewall configuration to restrict access to Acronis management interface
# Replace 10.0.0.0/24 with your trusted management network

# Linux iptables example
iptables -A INPUT -p tcp --dport 9877 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 9877 -j DROP

# Windows Firewall PowerShell example
New-NetFirewallRule -DisplayName "Restrict Acronis Management" -Direction Inbound -LocalPort 9877 -Protocol TCP -RemoteAddress 10.0.0.0/24 -Action Allow