CVE-2025-55177 – This WhatsApp vulnerability allows unauthorized... (How to Fix)

Q: What is the severity of CVE-2025-55177?

CVE-2025-55177 has a CVSS score of 5.4 (MEDIUM). This WhatsApp vulnerability allows unauthorized users to trigger processing of arbitrary URLs on a target's device through linked device synchronization messages. When combined with Apple OS vulnerability CVE-2025-43300, it could enable sophisticated attacks against specific users. Affected users include those running vulnerable WhatsApp versions on iOS and macOS.

📋 TL;DR

This WhatsApp vulnerability allows unauthorized users to trigger processing of arbitrary URLs on a target's device through linked device synchronization messages. When combined with Apple OS vulnerability CVE-2025-43300, it could enable sophisticated attacks against specific users. Affected users include those running vulnerable WhatsApp versions on iOS and macOS.

💻 Affected Systems

Products:

WhatsApp for iOS
WhatsApp Business for iOS
WhatsApp for Mac

Versions: WhatsApp for iOS prior to v2.25.21.73, WhatsApp Business for iOS prior to v2.25.21.78, WhatsApp for Mac prior to v2.25.21.78

Operating Systems: iOS, macOS

Default Config Vulnerable: ⚠️ Yes

Notes: Requires linked device synchronization feature to be enabled. Exploitation requires combination with Apple OS vulnerability CVE-2025-43300 for maximum impact.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Combined with CVE-2025-43300, could lead to remote code execution, data theft, or complete device compromise of targeted users.

🟠

Likely Case

Targeted exploitation by sophisticated actors to access sensitive WhatsApp data or device information from specific high-value targets.

🟢

If Mitigated

Limited to unauthorized URL processing without OS vulnerability, potentially causing denial of service or limited data exposure.

🌐 Internet-Facing: MEDIUM

🏢 Internal Only: LOW

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: CONFIRMED

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Confirmed exploited in sophisticated attacks against specific targeted users when combined with CVE-2025-43300. Requires attacker to send synchronization messages to target's linked devices.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: WhatsApp for iOS v2.25.21.73+, WhatsApp Business for iOS v2.25.21.78+, WhatsApp for Mac v2.25.21.78+

Vendor Advisory: https://www.facebook.com/security/advisories/cve-2025-55177

Restart Required: No

Instructions:

1. Open App Store on iOS device or Mac App Store on macOS. 2. Search for WhatsApp. 3. Tap 'Update' if available. 4. Alternatively, uninstall and reinstall latest version from official app stores.

🔧 Temporary Workarounds

Disable Linked Devices

all

Temporarily disable WhatsApp Web/Desktop linking to prevent synchronization message processing

Open WhatsApp > Settings > Linked Devices > Log Out from all devices

🧯 If You Can't Patch

Disable WhatsApp Web/Desktop linking completely
Apply Apple security updates for CVE-2025-43300 to reduce combined attack surface

🔍 How to Verify

Check if Vulnerable:

Check WhatsApp version in app settings: Settings > Help > App Info

Check Version:

Not applicable - check within app settings on iOS/macOS

Verify Fix Applied:

Verify version is WhatsApp for iOS v2.25.21.73+, WhatsApp Business for iOS v2.25.21.78+, or WhatsApp for Mac v2.25.21.78+

📡 Detection & Monitoring

Log Indicators:

Unusual linked device synchronization activity
Multiple failed synchronization attempts from unknown sources

Network Indicators:

Unexpected WhatsApp synchronization traffic to unusual endpoints
Suspicious URL processing requests

SIEM Query:

Not applicable for consumer mobile applications

📊 Metadata

CVE ID: CVE-2025-55177

CVSS v3 Score: 5.4 (MEDIUM)

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

CWE: CWE-863

EPSS Score: 0.95% exploit probability (75.9th percentile)

CISA KEV: Actively Exploited added Sep 2, 2025

Published: August 29, 2025

Last Updated: October 24, 2025

🔗 References

https://www.facebook.com/security/advisories/cve-2025-55177 Vendor Advisory
https://www.whatsapp.com/security/advisories/2025/ Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-55177 US Government Resource

📤 Share & Export

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🔗 Related Vulnerabilities

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