CVE-2025-43494
📋 TL;DR
A mail header parsing vulnerability in Apple operating systems allows attackers to cause persistent denial-of-service conditions. This affects users of iOS, iPadOS, macOS, watchOS, and visionOS who process email messages. The vulnerability stems from improper input validation when parsing mail headers.
💻 Affected Systems
- iOS
- iPadOS
- macOS
- watchOS
- visionOS
📦 What is this software?
Ipados by Apple
Ipados by Apple
Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Permanent disruption of mail services requiring system reinstallation or restoration from backup.
Likely Case
Mail application crashes or becomes unresponsive until system restart.
If Mitigated
Minimal impact with proper email filtering and updated systems.
🎯 Exploit Status
Exploitation requires sending specially crafted email messages to vulnerable systems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: watchOS 26.1, iOS 18.7.2 and iPadOS 18.7.2, macOS Tahoe 26.1, visionOS 26.1, macOS Sonoma 14.8.2, macOS Sequoia 15.7.2, iOS 26.1 and iPadOS 26.1
Vendor Advisory: https://support.apple.com/en-us/125632
Restart Required: Yes
Instructions:
1. Open Settings app. 2. Navigate to General > Software Update. 3. Download and install the latest available update. 4. Restart the device when prompted.
🔧 Temporary Workarounds
Disable Mail Processing
allTemporarily disable mail applications or services to prevent exploitation.
Email Filtering
allImplement email gateway filtering to block suspicious or malformed email headers.
🧯 If You Can't Patch
- Implement network-level email filtering to block malicious messages
- Restrict email access to trusted sources only
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions list in Settings > General > About.Check Version:
On macOS: sw_vers. On iOS/iPadOS: Settings > General > About > Version.Verify Fix Applied:
Verify system version matches or exceeds patched versions listed in the advisory.📡 Detection & Monitoring
Log Indicators:
- Mail application crash logs
- System logs showing mail service failures
- Repeated mail process restarts
Network Indicators:
- Unusual email traffic patterns
- Emails with malformed headers
SIEM Query:
source="mail.log" AND ("crash" OR "segfault" OR "denial of service")