CVE-2025-24209: Apple Safari Buffer Overflow Vulnerability

CVE-2025-24209 Overview

CVE-2025-24209 is a buffer overflow vulnerability affecting Apple Safari and multiple Apple operating systems. The vulnerability exists due to improper memory handling when processing web content. An attacker could exploit this flaw by crafting malicious web content that, when processed by a vulnerable application, triggers a buffer overflow condition leading to an unexpected process crash.

This memory corruption issue poses a significant risk to users across Apple's ecosystem, as it affects the core web rendering engine shared by Safari, iOS, iPadOS, macOS, tvOS, and watchOS. The vulnerability requires network-based delivery of malicious content, making drive-by attacks a potential exploitation vector.

Critical Impact

Processing maliciously crafted web content may lead to an unexpected process crash, potentially enabling denial of service attacks against affected Apple devices and applications.

Affected Products

• Apple Safari (versions prior to 18.4)
• Apple iOS and iPadOS (versions prior to 18.4 and iPadOS 17.7.6)
• Apple macOS Sequoia (versions prior to 15.4)
• Apple tvOS (versions prior to 18.4)
• Apple watchOS (versions prior to 11.4)

Discovery Timeline

• March 31, 2025 - CVE-2025-24209 published to NVD
• April 2026 - Last updated in NVD database

Technical Details for CVE-2025-24209

Vulnerability Analysis

This buffer overflow vulnerability (CWE-120: Buffer Copy without Checking Size of Input) occurs within Apple's WebKit-based rendering components. The flaw stems from insufficient bounds checking when handling specially crafted web content, allowing data to be written beyond allocated buffer boundaries.

The vulnerability can be triggered remotely through network-delivered content, though exploitation requires specific conditions to be met, resulting in higher attack complexity. When successfully exploited, the vulnerability can impact confidentiality and integrity to a limited degree while causing significant availability impact through process crashes.

Root Cause

The root cause of CVE-2025-24209 is a classic buffer overflow condition where the application fails to properly validate the size of input data before copying it into a fixed-size memory buffer. In the context of web content processing, this occurs when parsing or rendering specific elements that exceed expected boundaries.

Apple addressed this issue by implementing improved memory handling routines that properly validate buffer sizes and enforce appropriate boundaries during content processing operations.

Attack Vector

The attack vector for CVE-2025-24209 is network-based, requiring an attacker to deliver maliciously crafted web content to a victim's device. Potential attack scenarios include:

• Drive-by Downloads: Victims visit a compromised or malicious website hosting the exploit payload
• Malicious Advertisements: Exploit code embedded in advertising networks reaches users through legitimate websites
• Phishing Campaigns: Attackers send links to malicious pages via email or messaging platforms
• Man-in-the-Middle Attacks: Network attackers inject malicious content into unencrypted web traffic

The vulnerability does not require user authentication or special privileges, though exploitation complexity is considered high due to the specific conditions required to trigger the buffer overflow.

Detection Methods for CVE-2025-24209

Indicators of Compromise

• Unexpected Safari or WebKit process crashes, particularly when browsing unfamiliar websites
• Crash reports indicating memory corruption or buffer overflow in WebKit-related components
• Unusual network traffic patterns to suspicious domains delivering web content
• System logs showing repeated com.apple.WebKit process terminations

Detection Strategies

• Monitor system crash logs for WebKit and Safari process crashes with memory-related error signatures
• Implement network-based intrusion detection systems to identify potentially malicious web content delivery attempts
• Deploy endpoint detection solutions capable of identifying buffer overflow exploitation attempts
• Track software versions across managed devices to identify unpatched systems vulnerable to CVE-2025-24209

Monitoring Recommendations

• Enable crash reporting and centralize crash logs from all Apple devices in your environment
• Configure web filtering solutions to block access to known malicious domains
• Implement browser isolation technologies to contain potential exploitation attempts
• Monitor for unusual Safari or WebKit behavior patterns across enterprise endpoints

How to Mitigate CVE-2025-24209

Immediate Actions Required

• Update Safari to version 18.4 or later immediately
• Update iOS and iPadOS devices to version 18.4 or later, or iPadOS 17.7.6 for older iPads
• Update macOS Sequoia to version 15.4 or later
• Update tvOS to version 18.4 and watchOS to version 11.4
• Enable automatic software updates on all Apple devices to receive future security patches

Patch Information

Apple has released security updates addressing CVE-2025-24209 with improved memory handling. The following updates contain the fix:

For detailed patch information, refer to the official Apple security advisories:

• Apple Support Article #122371
• Apple Support Article #122372
• Apple Support Article #122373
• Apple Support Article #122377
• Apple Support Article #122379

Additionally, Debian has released updates for affected packages. See the Debian LTS Announcement for details on Linux distributions using WebKit.

Workarounds

• Use alternative browsers that do not rely on WebKit until patches can be applied
• Implement web content filtering to block potentially malicious sites
• Enable content blockers in Safari to reduce exposure to malicious web content
• Consider using network-level security controls to inspect and filter web traffic
• Deploy browser isolation solutions for high-risk users who cannot immediately update

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

# Check for available software updates on macOS
softwareupdate --list

# Install all available updates
softwareupdate --install --all