CVE-2026-43738 Overview
CVE-2026-43738 is an out-of-bounds read vulnerability [CWE-125] in Apple macOS asset catalog processing. Processing a maliciously crafted asset catalog may result in disclosure of process memory. Apple addressed the issue with improved memory handling in macOS Sequoia 15.7.8 and macOS Sonoma 14.8.8. The flaw requires local access and user interaction, limiting remote exploitation but posing risk when users open untrusted files or applications bundling asset catalogs.
Critical Impact
Local attackers can disclose sensitive process memory contents by inducing a user to process a crafted asset catalog, potentially exposing secrets, pointers useful for defeating ASLR, or other in-memory data.
Affected Products
- Apple macOS Sonoma versions prior to 14.8.8
- Apple macOS Sequoia versions prior to 15.7.8
- Applications and system components that parse asset catalog (.car) files on affected macOS versions
Discovery Timeline
- 2026-07-27 - CVE-2026-43738 published to NVD
- 2026-07-28 - Last updated in NVD database
Technical Details for CVE-2026-43738
Vulnerability Analysis
The vulnerability resides in the macOS component responsible for parsing asset catalog files. Asset catalogs (.car) are compiled resource bundles used by macOS and iOS applications to store images, colors, and other UI assets. When the parser processes a malformed catalog, it reads beyond the bounds of an allocated buffer.
Out-of-bounds reads [CWE-125] return adjacent memory contents to the caller. In this case, the returned data may include process memory belonging to the application handling the catalog. Attackers can chain this primitive with other flaws to bypass mitigations such as Address Space Layout Randomization (ASLR).
Exploitation requires local delivery of the crafted catalog and user interaction, such as opening an application or document containing the malicious asset. The vulnerability does not directly permit code execution or integrity impact, but the leaked memory can accelerate follow-on attacks.
Root Cause
The root cause is missing or insufficient bounds validation during asset catalog deserialization. Length or offset fields embedded in the catalog file are trusted without validation against the actual buffer size. Apple's advisory states the issue was resolved by improved memory handling, indicating stricter bounds checks were added to the parser.
Attack Vector
An attacker crafts an asset catalog with manipulated structural fields and delivers it via an application bundle, document, or download. When the user opens the file or launches the application, the vulnerable parser reads out-of-bounds memory and exposes contents to attacker-controlled logic within the process. The captured memory can be exfiltrated through the application's normal I/O channels.
No public exploit or proof-of-concept is available at this time. See Apple Support Advisory #128071 and Apple Support Advisory #128072 for vendor details.
Detection Methods for CVE-2026-43738
Indicators of Compromise
- Unexpected .car asset catalog files delivered via email attachments, external downloads, or unsigned application bundles
- Application crash reports referencing asset catalog parsing routines or CoreUI framework fault addresses
- Unsigned or ad-hoc signed macOS applications bundling non-standard asset catalog resources
Detection Strategies
- Monitor endpoints running macOS versions earlier than 14.8.8 (Sonoma) or 15.7.8 (Sequoia) for exposure inventory
- Inspect application bundles for anomalous Assets.car sizes or entropy patterns inconsistent with legitimate builds
- Correlate process crash telemetry with recent file opens involving asset catalog resources
Monitoring Recommendations
- Enable macOS unified logging and forward crash reports to a central analysis pipeline
- Track code-signing status and notarization results for applications introduced onto managed endpoints
- Alert on execution of unsigned applications originating from user download directories
How to Mitigate CVE-2026-43738
Immediate Actions Required
- Upgrade affected endpoints to macOS Sonoma 14.8.8 or macOS Sequoia 15.7.8 or later
- Enforce Gatekeeper and notarization requirements to block execution of untrusted application bundles
- Restrict opening of asset catalog files and unsigned applications received from external sources
Patch Information
Apple resolved CVE-2026-43738 in macOS Sonoma 14.8.8 and macOS Sequoia 15.7.8 with improved memory handling in the asset catalog parser. Refer to Apple Support Advisory #128071 for macOS Sequoia and Apple Support Advisory #128072 for macOS Sonoma. Apply updates through System Settings > General > Software Update or via MDM.
Workarounds
- No official workaround exists; applying the vendor patch is the only complete remediation
- Limit user privileges and enforce application allowlisting to reduce exposure to untrusted catalogs
- Educate users to avoid opening applications or documents from unverified sources until patches are deployed
# Verify macOS build version on managed endpoints
sw_vers -productVersion
# Trigger software update check via command line
sudo softwareupdate --list
sudo softwareupdate --install --all --restart
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
