Critical Symantec DLP Agent Flaw (CVE-2024-XXXX) Lets Attackers Escalate Privileges

Key Takeaways

• A critical privilege escalation flaw (CVE-2026-3991) has been discovered in the Symantec Data Loss Prevention (DLP) Agent for Windows.
• The vulnerability allows a local attacker with low privileges to elevate their access to SYSTEM-level permissions.
• The flaw stems from a hardcoded OpenSSL configuration path that can be manipulated by an attacker.
• Symantec DLP Agents before versions 16.1 MP2 or 25.1 MP1 are affected.
• Patches have been released by Broadcom and immediate updates are strongly recommended.

A severe security vulnerability has been identified within the Symantec Data Loss Prevention (DLP) Agent for Windows, posing a significant risk to enterprise environments. This flaw, designated as CVE-2026-3991, enables a local attacker with minimal access privileges to achieve full system control.

The vulnerability carries a high CVSS score of 7.8 and requires no specialized configuration to be exploited, leaving default installations of the agent exposed. Security researcher Manuel Feifel is credited with discovering the flaw, prompting Broadcom, the vendor, to issue immediate patches.

Symantec DLP Agent Vulnerability Details

The root cause of this critical issue lies in the compilation and integration of the OpenSSL library within the Symantec DLP Agent. The library was built with a hardcoded configuration path pointing to a specific development directory that is typically absent from standard Windows installations.

Crucially, Windows often permits authenticated users to create missing directories at the root level. This permission allows a low-privileged user to reconstruct the non-existent development path. The vulnerable process, edpa.exe, operates with SYSTEM privileges, making this particularly dangerous.

Upon startup, or when an OpenSSL initialization event occurs, the edpa.exe process attempts to locate its OpenSSL configuration file (openssl.cnf) at this hardcoded, attacker-controllable location.

To successfully exploit CVE-2026-3991, an attacker with basic local access needs to perform the following steps:

• The attacker first creates the specific missing directory structure: C:VontuDevworkDiropenssloutputx64ReleaseSSL.
• Next, they place a malicious OpenSSL.cnf file and a payload DLL into this newly created directory.
• The specially crafted configuration file utilizes the standard OpenSSL directive dynamic_path to directly point to the attacker’s malicious DLL.
• When the Symantec DLP Agent service restarts or initializes OpenSSL, it reads the malicious configuration file.
• The system then loads the attacker’s DLL as a dynamic engine, executing its code immediately with SYSTEM privileges.

This attack vector is particularly hazardous for enterprise networks because the malicious code executes directly within the highly trusted DLP agent process. This allows threat actors to bypass conventional endpoint security protections and completely evade system telemetry. Furthermore, by compromising this process, attackers can establish deep, persistent access on the host machine, appearing entirely legitimate to security monitoring tools.

Affected and Patched Versions

Broadcom was informed of this vulnerability in November 2025 and subsequently released an official security advisory and corrective patches on March 30, 2026. Organizations utilizing Symantec DLP are urged to update their Windows endpoint agents without delay to mitigate this severe threat.

The vulnerability impacts Symantec DLP Agents preceding versions 16.1 MP2 or 25.1 MP1. System administrators are strongly advised to upgrade to one of the following fixed versions of Data Loss Prevention (DLP): DLP 25.1 MP1, DLP 16.1 MP2, DLP 16.0 RU2 HF9, DLP 16.0 RU1 MP1 HF12, and DLP 16.0 MP2 HF15, as detailed in the Infoguard Labs advisory.

Prioritizing these patches is crucial, especially in environments where insider threats, local privilege escalation, or lateral movement within the network represent significant security concerns.

What You Should Do

• Immediately identify all Symantec DLP Agents running on Windows systems within your environment.
• Verify the current version of your Symantec DLP Agents.
• Upgrade all affected agents to one of the patched versions: DLP 25.1 MP1, DLP 16.1 MP2, DLP 16.0 RU2 HF9, DLP 16.0 RU1 MP1 HF12, or DLP 16.0 MP2 HF15.
• Monitor your endpoints for any unusual activity, especially after applying patches, to ensure no prior exploitation attempts occurred.
• Review and reinforce endpoint security configurations to limit default permissions for low-privileged users where possible, although this specific vulnerability is addressed by the patch.

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