CVE-2025-43431: Apple Safari Buffer Overflow Vulnerability

CVE-2025-43431 Overview

CVE-2025-43431 is a memory corruption vulnerability affecting Apple Safari and multiple Apple operating systems including iOS, iPadOS, macOS Tahoe, tvOS, visionOS, and watchOS. The vulnerability stems from improper memory handling when processing maliciously crafted web content, which can lead to memory corruption with potential for arbitrary code execution.

Critical Impact

Attackers can exploit this vulnerability by tricking users into visiting a malicious webpage, potentially leading to memory corruption that could allow unauthorized code execution within the context of the affected application.

Affected Products

• Apple Safari (versions prior to 26.1)
• iOS 18.7.2 and earlier, iOS prior to 26.1
• iPadOS 18.7.2 and earlier, iPadOS prior to 26.1
• macOS Tahoe (versions prior to 26.1)
• tvOS (versions prior to 26.1)
• visionOS (versions prior to 26.1)
• watchOS (versions prior to 26.1)

Discovery Timeline

• 2025-11-04 - CVE-2025-43431 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2025-43431

Vulnerability Analysis

This vulnerability is classified under CWE-787 (Out-of-Bounds Write) and CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists in the WebKit rendering engine's memory handling routines when processing web content.

When Safari or a WebKit-based component encounters specially crafted web content, the memory handling code fails to properly validate buffer boundaries during operations. This improper handling allows an attacker to corrupt memory structures, potentially overwriting critical data or gaining control of program execution flow.

The vulnerability requires user interaction—specifically, the victim must visit a malicious website or open a document containing the exploit payload. The attack is network-based and does not require authentication or elevated privileges on the attacker's part.

Root Cause

The root cause of CVE-2025-43431 lies in insufficient bounds checking within WebKit's memory management routines. When the browser processes certain types of web content, the affected code path does not adequately validate memory operations, leading to out-of-bounds write conditions. This type of vulnerability (CWE-787) allows data to be written beyond allocated buffer boundaries, corrupting adjacent memory regions.

Attack Vector

The attack vector for this vulnerability is network-based and requires user interaction. An attacker would typically:

1. Create a malicious webpage containing specially crafted content designed to trigger the memory corruption
2. Distribute the link through phishing emails, social engineering, or compromised legitimate websites
3. When a victim navigates to the malicious page using a vulnerable Safari version or WebKit-based application, the crafted content triggers the out-of-bounds write
4. Successful exploitation can corrupt memory structures, potentially allowing the attacker to execute arbitrary code or cause application crashes

The vulnerability affects all Apple platforms utilizing WebKit, making it particularly impactful given the wide deployment of Safari across Apple's ecosystem. For detailed technical information, refer to the Apple Support Advisory #125632 and related security bulletins.

Detection Methods for CVE-2025-43431

Indicators of Compromise

• Unexpected Safari or WebKit process crashes, particularly when visiting untrusted websites
• Unusual memory allocation patterns or memory exhaustion in Safari processes
• Detection of known malicious domains attempting to serve exploit payloads
• WebKit-related crash reports containing memory corruption signatures

Detection Strategies

• Monitor Safari and WebKit process behavior for abnormal memory operations or crash patterns
• Implement web filtering solutions to block known malicious domains associated with WebKit exploits
• Deploy endpoint detection and response (EDR) solutions capable of detecting memory corruption attempts
• Review system logs for WebKit crash reports indicating potential exploitation attempts

Monitoring Recommendations

• Enable and centralize logging for Safari and WebKit processes across managed Apple devices
• Configure alerts for repeated browser crashes that may indicate exploitation attempts
• Monitor network traffic for connections to suspicious or newly registered domains
• Utilize SentinelOne's behavioral AI to detect anomalous process behavior indicative of memory corruption exploits

How to Mitigate CVE-2025-43431

Immediate Actions Required

• Update Safari to version 26.1 or later immediately
• Update iOS devices to version 26.1 or 18.7.2 or later
• Update iPadOS devices to version 26.1 or 18.7.2 or later
• Update macOS Tahoe to version 26.1 or later
• Update tvOS, visionOS, and watchOS to version 26.1 or later

Patch Information

Apple has addressed this vulnerability in multiple security updates. Organizations should prioritize patching all affected Apple devices. Refer to the official Apple Security Advisories for complete patch information:

• Apple Support Advisory #125632
• Apple Support Advisory #125633
• Apple Support Advisory #125634
• Apple Support Advisory #125637
• Apple Support Advisory #125638
• Apple Support Advisory #125639
• Apple Support Advisory #125640

Workarounds

• Restrict access to untrusted websites using web content filtering until patches can be applied
• Consider using alternative browsers on macOS where possible until Safari is updated
• Implement network-level protections to block known exploit delivery domains
• Educate users about the risks of clicking links from untrusted sources

# Check Safari version on macOS
/Applications/Safari.app/Contents/MacOS/Safari --version

# Verify iOS/iPadOS version via command line (requires MDM or developer tools)
# Settings > General > About > Software Version should show 26.1 or 18.7.2+