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CVE-2026-28709 is a vulnerability in Acronis Cyber Protect 17 caused by improper authorization checks, falling under CWE-863 (Incorrect Authorization) . This flaw allows an authenticated attacker with low privileges to manipulate resources they should not have access to, without requiring any user interaction. The vulnerability exists in builds prior to 41186 for both Linux and Windows platforms. The attack vector is network-based with low complexity, meaning it can be exploited remotely without special conditions. While confidentiality and availability remain unaffected, the integrity impact is low, allowing unauthorized modification of certain resources . Acronis addressed this issue in build 41186, and users are strongly advised to update to this version or later .
dailycve form:
Platform: Acronis Cyber Protect
Version: Before build 41186
Vulnerability: Incorrect Authorization
Severity: 4.3 MEDIUM
Date: 03/12/2026
Prediction: Patch already available
What Undercode Say:
Analytics
The vulnerability scoring indicates a network-based attack vector (AV:N) with low attack complexity (AC:L), making it relatively easy to exploit once authenticated. The requirement for low privileges (PR:L) suggests that even standard users could potentially exploit this flaw. With no user interaction needed (UI:N) and an unchanged scope (S:U), the exploitation path is straightforward. The impact is limited to integrity (I:L), meaning an attacker could modify data but not access confidential information or disrupt services . This type of vulnerability is particularly concerning in multi-tenant environments where resource isolation is critical.
Bash commands and codes
To check your current Acronis Cyber Protect 17 build version on Linux:
Check Acronis Cyber Protect version cat /opt/acronis/version.txt | grep "Build" Alternative method using rpm (if installed via RPM) rpm -q acronis-cyber-protect For Debian-based systems dpkg -l | grep acronis
To verify the build number on Windows (PowerShell):
Check Acronis installation details
Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\" | Where-Object {$_.DisplayName -like "Acronis Cyber Protect"} | Select-Object DisplayName, DisplayVersion
Check specific build from installation directory
Get-Item "C:\Program Files\Acronis\CyberProtect\" | Select-Object Name, LastWriteTime
Update commands for Linux:
Update Acronis Cyber Protect to the latest version sudo apt update && sudo apt upgrade acronis-cyber-protect Debian/Ubuntu sudo yum update acronis-cyber-protect RHEL/CentOS sudo dnf update acronis-cyber-protect Fedora/RHEL 8+
How Exploit
To exploit CVE-2026-28709, an attacker would need:
- Valid low-privileged credentials to the Acronis Cyber Protect installation
2. Network access to the affected system
- Knowledge of the specific API endpoints or resources vulnerable to improper authorization
The exploitation process would involve:
- Authenticating to the Acronis Cyber Protect interface or API
- Sending crafted requests to manipulate resources that should be restricted
- Bypassing authorization checks due to missing or insufficient validation
- Modifying protected resources without proper permissions
Proof of concept would likely demonstrate that a standard user could modify backup configurations, protection plans, or other settings reserved for administrators.
Protection from this CVE
To protect against CVE-2026-28709:
- Immediate update: Upgrade to Acronis Cyber Protect 17 build 41186 or later :
– Download from official Acronis website
– Apply through the product’s built-in update mechanism
– Verify successful update by checking build number
2. Temporary mitigations (if update cannot be applied immediately):
– Restrict network access to Acronis Cyber Protect services
– Implement strict firewall rules limiting access to trusted IPs
– Review and minimize user accounts with access to the system
– Enable comprehensive logging and monitor for suspicious resource access patterns
– Apply principle of least privilege for all user accounts
3. Verification steps after patching:
- Confirm build number is 41186 or higher
- Test authorization controls to ensure proper enforcement
- Review security logs for any prior exploitation attempts
Impact
The impact of CVE-2026-28709 includes:
- Integrity compromise: Attackers can modify resources without authorization
- Configuration tampering: Backup policies, protection settings, or other critical configurations could be altered
- Potential compliance violations: Unauthorized changes to protected data or systems may breach regulatory requirements
- Operational disruption: Modified resources could lead to backup failures or incorrect protection configurations
- Privilege escalation chain: While limited to integrity impact alone, this could be combined with other vulnerabilities for greater effect
The CVSS score of 4.3 (MEDIUM) reflects the limited scope of impact, but in enterprise environments where Acronis Cyber Protect manages critical backup and protection tasks, unauthorized manipulation could have significant downstream effects on data protection and disaster recovery capabilities .
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Sources:
Reported By: nvd.nist.gov
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