CVE-2026-43790 is an out of bounds write in macOS (CVSS 9.1, critical). A remote attacker may be able to cause unexpected system termination or corrupt kernel memory. Apple fixed it in macOS Golden Gate 27, macOS Sequoia 15.8 and macOS Tahoe 26.7, so update to the release for your line.
What's affected
The record says the issue is fixed in:
- macOS Golden Gate 27
- macOS Sequoia 15.8
- macOS Tahoe 26.7
Earlier builds on those release lines are affected. Apple's three support pages in the record cover the releases, and I did not retrieve them. Apple's description is brief, saying only that memory handling was improved.
How to check if you're exposed
On each Mac, run:
sw_vers
and compare the product version with the fixed releases above. For a fleet, use your device management tool to report macOS versions, and look for machines that are behind on their release line.
Macs that are out of Apple support and cannot reach these releases remain exposed, so list them too.
What to do now
- Update every Mac to the fixed release for its line.
- Use device management to set a deadline and force the update on managed machines.
- Identify Macs that cannot upgrade and plan their replacement, or limit their network exposure.
- Verify the version after updating with sw_vers.
- Keep automatic updates on for personal and unmanaged devices.
Why it matters
The weakness is CWE-787, out of bounds write. Kernel memory is the most sensitive memory on a machine. A write outside its intended bounds can crash the system or give an attacker influence over what the kernel does next.
The score reflects a network vector with no login or user action, and high impact on integrity and availability. Apple's note does not say the issue is exploited, and the KEV flag in the record is false.
Quick check
Which update should I install?
The one for your release line: Sequoia 15.8, Tahoe 26.7 or Golden Gate 27, as the record lists.
Sources
- Apple security release 149035 (listed in the NVD record, not retrieved)
- Apple security release 149042 (listed in the NVD record, not retrieved)
- Apple security release 149043 (listed in the NVD record, not retrieved)
- Gold page for this CVE
Last reviewed: 19 October 2026.
