CVE-2025-53599 – This vulnerability allows attackers to execute ... (How to Fix)

Q: What is the severity of CVE-2025-53599?

CVE-2025-53599 has a CVSS score of 9.8 (CRITICAL). This vulnerability allows attackers to execute malicious JavaScript code in Whale browser for iOS by exploiting a flaw in how the browser handles crafted JavaScript schemes. Users running vulnerable versions of Whale browser on iOS are affected. The attack requires user interaction such as clicking a malicious link.

📋 TL;DR

This vulnerability allows attackers to execute malicious JavaScript code in Whale browser for iOS by exploiting a flaw in how the browser handles crafted JavaScript schemes. Users running vulnerable versions of Whale browser on iOS are affected. The attack requires user interaction such as clicking a malicious link.

💻 Affected Systems

Products:

Whale browser for iOS

Versions: All versions before 3.9.1.4206

Operating Systems: iOS

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects Whale browser on iOS devices. Requires user to interact with malicious content.

📦 What is this software?

Whale by Navercorp

View all CVEs affecting Whale →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete compromise of browser session including theft of authentication cookies, session hijacking, credential theft, and potential access to sensitive data within the browser.

🟠

Likely Case

Cross-site scripting attacks leading to session hijacking, credential theft, and unauthorized actions within the browser context.

🟢

If Mitigated

Limited impact if browser sandboxing works properly, potentially restricted to browser session only without system compromise.

🌐 Internet-Facing: HIGH - Attack can be delivered via malicious websites, emails, or messages that users might click on.

🏢 Internal Only: MEDIUM - Requires user interaction with malicious content, which could be delivered internally via phishing or compromised internal sites.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires user interaction but is technically simple once malicious content is delivered.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 3.9.1.4206

Vendor Advisory: https://cve.naver.com/detail/cve-2025-53599.html

Restart Required: Yes

Instructions:

1. Open App Store on iOS device 2. Search for Whale browser 3. Tap Update button 4. Restart browser after update completes

🔧 Temporary Workarounds

Disable JavaScript

ios

Temporarily disable JavaScript execution in Whale browser settings

Use alternative browser

ios

Switch to a different browser until Whale is updated

🧯 If You Can't Patch

Implement web filtering to block malicious JavaScript schemes
Educate users to avoid clicking suspicious links and enable browser security features

🔍 How to Verify

Check if Vulnerable:

Check Whale browser version in Settings > About

Check Version:

Open Whale browser > Settings > About to view version

Verify Fix Applied:

Verify version is 3.9.1.4206 or higher in browser settings

📡 Detection & Monitoring

Log Indicators:

Unusual JavaScript scheme executions
Multiple failed JavaScript scheme attempts

Network Indicators:

Requests to known malicious domains containing crafted JavaScript schemes

SIEM Query:

browser:whale AND event:javascript_execution AND scheme:malicious

📊 Metadata

CVE ID: CVE-2025-53599

CVSS v3 Score: 9.8 (CRITICAL)

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

CWE: CWE-79

EPSS Score: 0.06% exploit probability (19.2th percentile)

Published: July 4, 2025

Last Updated: October 1, 2025

🔗 References

https://cve.naver.com/detail/cve-2025-53599.html Vendor Advisory

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🔗 Related Vulnerabilities

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