CVE-2024-5840 – This CVE describes a Cross-Origin Resource Shar... (How to Fix)

Q: What is the severity of CVE-2024-5840?

CVE-2024-5840 has a CVSS score of 6.5 (MEDIUM). This CVE describes a Cross-Origin Resource Sharing (CORS) policy bypass vulnerability in Google Chrome that allows attackers to bypass discretionary access control via a crafted HTML page. It affects Chrome users running versions prior to 126.0.6478.54, potentially enabling unauthorized cross-origin requests.

📋 TL;DR

This CVE describes a Cross-Origin Resource Sharing (CORS) policy bypass vulnerability in Google Chrome that allows attackers to bypass discretionary access control via a crafted HTML page. It affects Chrome users running versions prior to 126.0.6478.54, potentially enabling unauthorized cross-origin requests.

💻 Affected Systems

Products:

Google Chrome
Chromium-based browsers

Versions: Versions prior to 126.0.6478.54

Operating Systems: Windows, Linux, macOS, ChromeOS

Default Config Vulnerable: ⚠️ Yes

Notes: All Chrome installations with default settings are vulnerable. Chromium-based browsers may also be affected depending on their CORS implementation.

📦 What is this software?

Chrome by Google

Google Chrome is the world's most popular web browser, used by over 3 billion users globally across Windows, macOS, Linux, Android, and iOS platforms. As a Chromium-based browser developed by Google, Chrome dominates the browser market with approximately 65% market share, making it a critical compon...

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Attackers could bypass same-origin policy protections to access sensitive user data from other websites, potentially leading to data theft, session hijacking, or unauthorized actions on behalf of the user.

🟠

Likely Case

Malicious websites could make unauthorized requests to other domains where the user is authenticated, potentially accessing limited user data or performing actions without proper authorization.

🟢

If Mitigated

With proper web application security controls like additional authentication checks and proper CORS configurations, the impact is limited to potential information disclosure rather than full account compromise.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires user interaction (visiting a malicious webpage). No public exploit code has been identified as of the advisory dates.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 126.0.6478.54 and later

Vendor Advisory: https://chromereleases.googleblog.com/2024/06/stable-channel-update-for-desktop.html

Restart Required: Yes

Instructions:

1. Open Chrome and click the three-dot menu > Help > About Google Chrome. 2. Chrome will automatically check for updates and install version 126.0.6478.54 or later. 3. Click 'Relaunch' to restart Chrome with the updated version.

🔧 Temporary Workarounds

Disable JavaScript for untrusted sites

all

Prevents malicious JavaScript from executing the CORS bypass attack

chrome://settings/content/javascript

Use browser extensions to block cross-origin requests

all

Extensions like uBlock Origin or NoScript can block suspicious cross-origin requests

🧯 If You Can't Patch

Use alternative browsers that are not affected by this specific Chrome vulnerability
Implement strict Content Security Policy (CSP) headers on web applications to limit cross-origin requests

🔍 How to Verify

Check if Vulnerable:

Open Chrome, go to chrome://version and check if version is less than 126.0.6478.54

Check Version:

google-chrome --version (Linux) or open chrome://version (all platforms)

Verify Fix Applied:

After updating, verify chrome://version shows 126.0.6478.54 or higher

📡 Detection & Monitoring

Log Indicators:

Unusual cross-origin requests in web server logs
Requests with unexpected Origin headers

Network Indicators:

Suspicious CORS preflight requests
Cross-origin requests to sensitive endpoints

SIEM Query:

web_access_logs | where user_agent contains "Chrome" and version < "126.0.6478.54" and (origin_header != expected_origin or cross_origin_request = true)

📊 Metadata

CVE ID: CVE-2024-5840

CVSS v3 Score: 6.5 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

CWE: CWE-284

Published: June 11, 2024

Last Updated: March 13, 2025

🔗 References

https://chromereleases.googleblog.com/2024/06/stable-channel-update-for-desktop.html Third Party Advisory
https://issues.chromium.org/issues/41492103 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7VXA32LXMNK3DSK3JBRLTBPFUH7LTODU/ Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MPU7AB53QQVNTBPGRMJRY5SXJNYWW3FX/ Third Party Advisory
https://chromereleases.googleblog.com/2024/06/stable-channel-update-for-desktop.html Third Party Advisory
https://issues.chromium.org/issues/41492103 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7VXA32LXMNK3DSK3JBRLTBPFUH7LTODU/ Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MPU7AB53QQVNTBPGRMJRY5SXJNYWW3FX/ Third Party Advisory

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