CVE-2026-64699 Overview
CVE-2026-64699 is an uninitialized memory use vulnerability [CWE-457] in Apple macOS. The flaw allows a local application to disclose kernel memory contents. Apple addressed the issue by improving memory initialization handling in the affected components.
The vulnerability affects multiple macOS versions and is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6. Exploitation requires local access and user interaction, limiting remote attack scenarios. Successful exploitation exposes sensitive kernel memory contents to an unprivileged application.
Critical Impact
A malicious application on the local system can read kernel memory, potentially revealing sensitive data such as cryptographic material, kernel pointers useful for defeating KASLR, or credentials residing in kernel structures.
Affected Products
- Apple macOS Sequoia prior to 15.7.8
- Apple macOS Sonoma prior to 14.8.8
- Apple macOS Tahoe prior to 26.6
Discovery Timeline
- 2026-07-27 - CVE-2026-64699 published to NVD
- 2026-07-28 - Last updated in NVD database
Technical Details for CVE-2026-64699
Vulnerability Analysis
The vulnerability is classified as Use of Uninitialized Resource [CWE-457]. A kernel code path returns memory to userspace without properly initializing all bytes of the buffer. The uninitialized bytes contain residual data from prior kernel operations.
An attacker running an application on the local machine can invoke the vulnerable code path and observe the leaked bytes. The disclosed content may include kernel pointers, stack contents, or cached data from other processes. Kernel pointer disclosure is particularly useful for bypassing Kernel Address Space Layout Randomization (KASLR) as a precursor to further kernel exploitation.
Apple's remediation initializes the affected memory before returning it to user-controlled contexts. Apple has not disclosed the specific subsystem in the public advisory. Further technical details can be found in the Apple Support Article #128067, Apple Support Article #128071, and Apple Support Article #128072.
Root Cause
The root cause is a kernel routine that allocates or reuses a memory region and copies it into a user-accessible buffer without zeroing or fully populating each field. Structure padding bytes and unused fields are common sources of such leaks in kernel interfaces.
Attack Vector
Exploitation requires local code execution on the target macOS system and user interaction. A user must run a malicious or trojanized application. Once executed, the application invokes the vulnerable interface and reads back kernel memory contents through the returned data structure.
No verified public proof-of-concept exists at the time of writing. The vulnerability mechanism is described in prose based on Apple's advisory language, and no exploitation code is available for reference.
Detection Methods for CVE-2026-64699
Indicators of Compromise
- Unsigned or ad-hoc signed binaries executing system calls that return kernel-provided buffers in unusual volumes.
- Applications making repeated calls to the same kernel interface in tight loops, consistent with harvesting leaked memory.
- Unexpected processes reading /dev/kmem-adjacent interfaces or making atypical sysctl and IOKit queries.
Detection Strategies
- Monitor endpoint telemetry for newly installed macOS applications on hosts that have not yet been patched to 15.7.8, 14.8.8, or 26.6.
- Correlate process execution events with subsequent privilege escalation attempts, since kernel memory disclosure is typically a precursor stage.
- Baseline normal user-mode syscall patterns and alert on outliers involving kernel data retrieval APIs.
Monitoring Recommendations
- Track macOS version inventory to identify hosts still running vulnerable builds.
- Log application installations from outside the Mac App Store and notarization-bypassed binaries.
- Retain process execution and code-signing telemetry for retrospective hunting once IOCs become public.
How to Mitigate CVE-2026-64699
Immediate Actions Required
- Update all macOS endpoints to macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, or macOS Tahoe 26.6.
- Prioritize systems handling sensitive data or used by privileged users such as administrators and developers.
- Restrict installation of unsigned or unnotarized applications through Gatekeeper policy enforcement.
Patch Information
Apple released fixes in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6. Refer to Apple Support Article #128067, Apple Support Article #128071, and Apple Support Article #128072 for the corresponding security content.
Workarounds
- No vendor-supplied workaround exists; applying the security update is the only supported remediation.
- Reduce risk by limiting local application execution to signed, notarized software from trusted publishers.
- Enforce least privilege for local user accounts to reduce the value of any leaked kernel data.
# Verify macOS build and apply pending security updates
sw_vers -productVersion
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.
