CVE-2026-41952

Executive Summary

CVE-2026-41952 is a local privilege escalation vulnerability affecting Acronis DeviceLock DLP and Acronis Cyber Protect Cloud Agent on Windows. The flaw stems from improper input validation, allowing a low-privileged local attacker to escalate privileges to SYSTEM. With a CVSS score of 7.8, this vulnerability poses a significant risk in enterprise environments where these agents are deployed for endpoint protection and data loss prevention. No public proof-of-concept or exploit code is currently available, and the EPSS score is 0.0%, indicating low exploitation activity at this time. However, the lack of a public patch status (UNKNOWN/UNPATCHED) raises concerns for organizations relying on these products.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects proprietary Windows software distributed by Acronis. Organizations should verify the integrity of their Acronis installations and ensure they are sourced from official channels.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Base Score: 7.8 (High)
• Attack Vector: Local (AV:L) – The attacker must have local access to the system.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: Low (PR:L) – The attacker needs initial low-privileged access.
• User Interaction: None (UI:N) – No user action is required.
• Scope: Unchanged (S:U) – The vulnerability does not cross trust boundaries.
• Confidentiality Impact: High (C:H) – Full system compromise possible.
• Integrity Impact: High (I:H) – Attacker can modify system files.
• Availability Impact: High (A:H) – Potential for denial of service.

Threat Level: High. Local privilege escalation vulnerabilities in security software are particularly dangerous as they can be used to disable or bypass the very protection the software provides.

Deep Dive & Mechanics

The vulnerability exists in the input validation logic of Acronis DeviceLock DLP and Cyber Protect Cloud Agent. These products run with high integrity (SYSTEM) privileges to enforce device control and security policies. The improper input validation allows a low-privileged user to send a crafted request or trigger a specific code path that fails to sanitize user-supplied data. This can lead to a buffer overflow, arbitrary write, or command injection, ultimately resulting in code execution in the context of the SYSTEM account.

Key Technical Details:

• Affected Component: Likely a service or driver that processes user input from low-privileged processes.
• Root Cause: Lack of proper bounds checking or validation of input parameters before use in privileged operations.
• Attack Vector: Local – The attacker must be able to execute code on the target machine (e.g., via malware, phishing, or as an insider threat).
• Prerequisites: Low-privileged user account on a Windows system with the vulnerable Acronis software installed.

Vulnerable vs. Patched Code

Since no specific code diff is publicly available, the following is a hypothetical example of the vulnerability pattern:

Vulnerable Code (C++ example):

void ProcessUserInput(char* userInput) {
    char buffer[256];
    // Improper input validation - no bounds check
    strcpy(buffer, userInput);
    // ... privileged operation using buffer
}

Patched Code:

void ProcessUserInput(char* userInput) {
    char buffer[256];
    // Proper input validation with bounds check
    if (strlen(userInput) >= sizeof(buffer)) {
        // Log error and reject input
        return;
    }
    strcpy_s(buffer, sizeof(buffer), userInput);
    // ... privileged operation using buffer
}

The patched version uses strcpy_s (or equivalent safe functions) and validates input length before copying.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Windows 10/11 VM with Acronis DeviceLock DLP build < 9.0.93212 or Cyber Protect Cloud Agent build < 42183.
• Low-privileged user account.
• Development tools (Visual Studio, Python, or Metasploit).

Exploitation Steps:

1. Reconnaissance: Identify the vulnerable service/process (e.g., DeviceLockService.exe or AcronisAgent.exe).
2. Craft Payload: Create a malicious input that triggers the improper validation. This could be a long string, a specially crafted file, or a specific API call.
3. Trigger Vulnerability: Execute the payload from the low-privileged context.
4. Escalate Privileges: The payload executes with SYSTEM privileges, allowing full control.

Example Payload (Conceptual):

import os
# Hypothetical exploit - replace with actual vulnerable API
os.system('echo "malicious_input" | DeviceLockCLI.exe --vuln-param')

Note: No public exploit code is available. This is a conceptual guide.

Blue Team (Defensive)

Detection & Prevention:

• Monitor Process Creation: Look for unusual child processes spawned by Acronis services (e.g., cmd.exe, powershell.exe).
• Audit Input Validation: Review logs for failed input validation attempts or crashes in Acronis components.
• Harden Systems: Apply the principle of least privilege; restrict local user accounts.
• Patch Management: Prioritize updating to patched builds (9.0.93212 for DeviceLock DLP, 42183 for Cyber Protect Cloud Agent).

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (None publicly available – monitor for new samples)
• Process Names: DeviceLockService.exe, AcronisAgent.exe, DeviceLockCLI.exe
• Registry Keys: HKLM\SOFTWARE\Acronis\DeviceLock (check for unauthorized modifications)
• Network Connections: Unusual outbound connections from Acronis processes (e.g., to unknown IPs)
• Event Logs: Windows Event ID 7031 (service crash), 4688 (process creation with suspicious parent-child relationships)

Detection Engineering

YARA Rule

rule CVE_2026_41952_Acronis_LPE {
    meta:
        description = "Detects potential exploitation of CVE-2026-41952 in Acronis products"
        author = "Valters IT"
        date = "2026-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-41952"
    strings:
        $s1 = "DeviceLockService.exe" ascii wide nocase
        $s2 = "AcronisAgent.exe" ascii wide nocase
        $s3 = "improper input validation" ascii wide nocase
        $hex1 = { 41 41 41 41 41 41 41 41 } // Pattern of long input
    condition:
        (uint16(0) == 0x5A4D or uint32(0) == 0x00004550) and
        (any of ($s1, $s2) or $s3 or $hex1)
}

Sigma Rule

title: CVE-2026-41952 - Acronis Local Privilege Escalation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects suspicious process creation from Acronis services
author: Valters IT
date: 2026/01/01
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith:
            - '\DeviceLockService.exe'
            - '\AcronisAgent.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\wscript.exe'
            - '\cscript.exe'
    condition: selection
falsepositives:
    - Legitimate administrative tasks
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (
    msg:"CVE-2026-41952 - Acronis LPE - Potential C2 Beacon";
    flow:to_server,established;
    content:"Acronis"; http_user_agent;
    pcre:"/DeviceLock|Cyber Protect/i";
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

1. Immediate Action: Update Acronis DeviceLock DLP to build 9.0.93212 or later, and Acronis Cyber Protect Cloud Agent to build 42183 or later.
2. Workaround: If patching is not immediately possible, restrict local user accounts and monitor Acronis service behavior.
3. Long-term: Implement application whitelisting (e.g., AppLocker) to prevent unauthorized executables from running.
4. Monitoring: Deploy the provided YARA, Sigma, and Suricata rules to detect exploitation attempts.
5. Vendor Contact: Monitor Acronis security advisories for official patches and additional guidance.

Valters IT

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