CVE-2026-28710: Acronis Cyber Protect Info Disclosure

CVE-2026-28710 Overview

CVE-2026-28710 is a critical authentication bypass vulnerability affecting Acronis Cyber Protect 17 on both Linux and Windows platforms. The vulnerability stems from improper authentication mechanisms that allow attackers to disclose sensitive information and manipulate data without proper credentials. This flaw affects all builds prior to build 41186.

Critical Impact

Unauthenticated attackers can remotely access and manipulate sensitive backup and protection data managed by Acronis Cyber Protect, potentially compromising enterprise data protection infrastructure.

Affected Products

• Acronis Cyber Protect 17 (Linux) before build 41186
• Acronis Cyber Protect 17 (Windows) before build 41186

Discovery Timeline

• 2026-03-06 - CVE-2026-28710 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2026-28710

Vulnerability Analysis

This vulnerability is classified under CWE-1390 (Weak Authentication), indicating a fundamental flaw in how Acronis Cyber Protect 17 validates user credentials and session tokens. The improper authentication implementation allows unauthorized users to bypass security controls that would normally restrict access to sensitive backup management functions.

The network-accessible nature of this vulnerability means attackers do not require any prior authentication or special privileges to exploit it. No user interaction is needed, making this particularly dangerous in enterprise environments where Acronis Cyber Protect manages critical backup infrastructure.

Root Cause

The root cause lies in improper authentication validation within Acronis Cyber Protect 17. The application fails to properly verify authentication tokens or credentials before granting access to protected resources and functionality. This weak authentication mechanism allows attackers to circumvent access controls entirely.

Attack Vector

The vulnerability is exploitable over the network without requiring any authentication credentials or user interaction. An attacker with network access to a vulnerable Acronis Cyber Protect installation can exploit the improper authentication to:

1. Access sensitive configuration and backup data without valid credentials
2. Manipulate backup settings and protection policies
3. Potentially compromise the integrity of backup operations

The attack does not require any privileges or special conditions, making exploitation straightforward for threat actors with network visibility to the target system. For detailed technical information, refer to the Acronis Security Advisory SEC-9137.

Detection Methods for CVE-2026-28710

Indicators of Compromise

• Unusual authentication attempts or access patterns to Acronis Cyber Protect management interfaces
• Unexpected modifications to backup configurations or protection policies
• Authentication logs showing successful access without corresponding valid credential entries
• Anomalous API calls to Acronis services from unexpected network locations

Detection Strategies

• Monitor network traffic for unauthorized connections to Acronis Cyber Protect services on default ports
• Implement alerting on authentication anomalies where access is granted without proper credential validation
• Review Acronis Cyber Protect access logs for signs of unauthorized administrative actions
• Deploy network intrusion detection rules targeting exploitation attempts against Acronis services

Monitoring Recommendations

• Enable verbose logging for all Acronis Cyber Protect authentication events
• Implement network segmentation to limit exposure of backup infrastructure
• Monitor for configuration changes to backup policies outside of authorized maintenance windows
• Correlate authentication events across backup infrastructure with SIEM solutions

How to Mitigate CVE-2026-28710

Immediate Actions Required

• Update Acronis Cyber Protect 17 to build 41186 or later immediately
• Restrict network access to Acronis Cyber Protect management interfaces to authorized IP ranges only
• Review audit logs for any signs of unauthorized access prior to patching
• Implement additional network-layer authentication controls until patching is complete

Patch Information

Acronis has released a security update addressing this vulnerability. Organizations should upgrade to Acronis Cyber Protect 17 build 41186 or later. The security advisory with full details is available at the Acronis Security Advisory SEC-9137.

Workarounds

• Implement network segmentation to isolate Acronis Cyber Protect from untrusted networks
• Configure firewall rules to restrict access to Acronis services to only trusted administrative hosts
• Enable additional authentication layers such as VPN requirements for management access
• Monitor and audit all access attempts to Acronis Cyber Protect until patching can be completed

# Example firewall rule to restrict access to Acronis management port
# Replace [TRUSTED_IP] with your management workstation IP
iptables -A INPUT -p tcp --dport 9876 -s [TRUSTED_IP] -j ACCEPT
iptables -A INPUT -p tcp --dport 9876 -j DROP