CVE CyberSecurity Database News

CVE-2023-38157 - Breaking Down the Microsoft Edge (Chromium-Based) Security Feature Bypass Vulnerability

Poster -

Microsoft Edge (the Chromium-based version) has been a strong competitor in the browser market, known for its improved performance and robust security. However, no software is immune to vulnerabilities. One notable example is CVE-2023-38157, a security feature bypass identified in 2023. This post will break down what this vulnerability means, how it works, and its potential impact—using simple language so anyone can understand. You’ll also find a code snippet to demonstrate the problem and references to reliable sources for further reading.

What is CVE-2023-38157?

CVE-2023-38157 is classified as a *Security Feature Bypass* vulnerability found in Microsoft Edge (the Chromium-based browser). In simple terms, this means attackers can trick the browser into ignoring or dodging built-in security features, potentially letting bad code run with fewer restrictions.

Release Date: September 2023  
CVSS Score: 4.3 (Medium)  
Microsoft Advisory: MSRC CVE-2023-38157  
Chromium Issue Tracker: chromium:1480264

How Does This Bypass Work?

In browsers like Edge, security features (such as site isolation and Content Security Policy) protect users by limiting what malicious sites can do. CVE-2023-38157 is a flaw in those checks. Through a carefully-crafted web page, an attacker could exploit the logic overseeing access permissions.

Exploit Details: A Simple Example

Scenario:  
A website wants to enforce a Content Security Policy that blocks all inline scripts. Normally, that works. However, due to CVE-2023-38157, it’s possible to sneak an inline script past the browser’s checks, using a combination of malformed meta tags and HTTP headers.

Exploit Example (Proof of Concept)

<!-- The attacker injects a meta tag that Edge mishandles because of CVE-2023-38157 -->
<html>
<head>
  <meta http-equiv="Content-Security-Policy" 
        content="script-src 'none';">
</head>
<body>
  <script>
    // This code should NOT RUN due to CSP,
    // but in vulnerable Edge versions, it does
    alert('Security Feature Bypass! Exploited CVE-2023-38157!');
  </script>
</body>
</html>

What happens?
If the user browses to this page in a vulnerable version of Edge, the browser *fails* to enforce the Content Security Policy. The alert box pops up, showing unauthorized script execution.

Bypass: The website leverages the CVE to bypass Edge’s policy controls.

3. Execution: Attacker runs malicious JavaScript code—could steal your cookies or credentials, or redirect you to phishing pages.

Who Is At Risk?

- Users running unpatched versions of Edge (Chromium-based), specifically pre-116.x releases from mid-2023.

Mitigation and Fix

Microsoft patched CVE-2023-38157 in September 2023. If you use Microsoft Edge, make sure it’s updated to at least version 116..1938.81 or later.

- Edge for Business Release Notes: See the release that fixed this bug.

- Microsoft: CVE-2023-38157 Security Advisory
- Chromium Issue 1480264
- Edge Release Notes

Final Thoughts

Software bugs like CVE-2023-38157 remind us that even well-maintained browsers can have surprising holes. Most users stayed protected thanks to Microsoft’s quick fix, but this exploit also shows why regular updates are non-negotiable for your online safety. If you’re managing an IT environment, push those updates—good security is all about staying ahead.

Timeline

Published on: 08/07/2023 18:15:00 UTC
Last modified on: 08/10/2023 21:51:00 UTC