CVE-2025-43221 Overview
CVE-2025-43221 is an out-of-bounds access vulnerability affecting multiple Apple operating systems. Processing a maliciously crafted media file may lead to unexpected app termination or corrupt process memory. The flaw is classified under CWE-125: Out-of-bounds Read and was addressed by Apple through improved bounds checking. The vulnerability requires local attack vector with user interaction, making exploitation reliant on a victim opening a crafted media file. Apple resolved the issue in iOS 18.6, iPadOS 18.6, macOS Sequoia 15.6, tvOS 18.6, and visionOS 2.6.
Critical Impact
Successful exploitation can corrupt process memory or terminate applications, potentially enabling further memory-corruption attack chains against Apple devices.
Affected Products
- Apple iOS and iPadOS prior to 18.6
- Apple macOS Sequoia prior to 15.6
- Apple tvOS prior to 18.6 and visionOS prior to 2.6
Discovery Timeline
- 2025-07-30 - CVE-2025-43221 published to NVD
- 2025-07-30 - Apple releases security advisories #124147, #124149, #124153, and #124154
- 2026-04-02 - Last updated in NVD database
Technical Details for CVE-2025-43221
Vulnerability Analysis
The vulnerability stems from an out-of-bounds memory access during the parsing of media files on Apple operating systems. When the affected media-processing component handles a maliciously crafted file, it reads memory beyond an allocated buffer boundary. This out-of-bounds access can corrupt adjacent process memory or cause the host application to terminate unexpectedly. Apple's advisories describe the fix as the addition of improved bounds checking, indicating the original code path lacked sufficient validation of length or offset fields parsed from the file. The attack requires local delivery of the media file and user interaction to open or render it.
Root Cause
The root cause is missing or insufficient bounds validation in a media-parsing routine shared across Apple operating systems. Untrusted size or offset values from the file format were used to index into a buffer without verification, resulting in an out-of-bounds read consistent with CWE-125.
Attack Vector
An attacker delivers a crafted media file to the target through email, messaging, downloads, or a malicious website. When the user opens the file, or a privileged application automatically parses it, the vulnerable code path is executed. The result is application termination or memory corruption that may be chained with other primitives to escalate impact.
No public proof-of-concept code has been associated with this CVE. See the Apple security advisory #124147 and the Full Disclosure mailing list posts for additional technical context.
Detection Methods for CVE-2025-43221
Indicators of Compromise
- Unexpected crashes of media-handling applications such as Preview, QuickTime, or Photos, with crash reports referencing out-of-bounds reads in media-parsing frameworks
- Repeated ReportCrash or spindump entries in unified logs tied to media file opens from untrusted sources
- Inbound media files with anomalous header fields, malformed atom sizes, or sizes inconsistent with file length
Detection Strategies
- Monitor endpoint telemetry for abnormal termination of media-processing processes correlated with file opens from email or browser downloads
- Inspect crash logs under ~/Library/Logs/DiagnosticReports/ for repeated faults in image, audio, or video decoder libraries
- Apply file-format validation at email and web gateways to flag media files with structurally invalid metadata
Monitoring Recommendations
- Track operating system versions across the fleet to identify devices still running Apple OS releases prior to the fixed versions
- Alert on processes that crash within seconds of opening a media file delivered from an external source
- Correlate crash events with user activity to identify potential targeted delivery of malicious media content
How to Mitigate CVE-2025-43221
Immediate Actions Required
- Update affected devices to iOS 18.6, iPadOS 18.6, macOS Sequoia 15.6, tvOS 18.6, or visionOS 2.6 or later
- Prioritize patching for users who routinely receive media files from external parties
- Educate users to avoid opening unsolicited media attachments and to verify senders before previewing files
Patch Information
Apple addressed CVE-2025-43221 by introducing improved bounds checking in the affected media-parsing code path. Refer to the official advisories for build numbers and update guidance: Apple Security Advisory #124147, #124149, #124153, and #124154.
Workarounds
- Restrict opening of media files from untrusted sources until updates are deployed
- Configure email and web gateways to scan or sandbox inbound media attachments
- Use mobile device management (MDM) policies to enforce minimum OS versions on managed Apple devices
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
