AI analysis
CVE-2026-43677 is an out-of-bounds write vulnerability in Apple's WebDAV connectivity code on macOS, fixed by removing the vulnerable code entirely. It is triggered when a user connects their Mac to a malicious WebDAV server, such as by mounting an untrusted WebDAV share via Finder. Apple describes the practical impact as unexpected app termination, though out-of-bounds writes are a memory-corruption class that can sometimes carry greater consequences than denial of service. All Macs running macOS Sequoia before 15.8, macOS Tahoe before 26.7, or macOS Golden Gate before 27 are affected until patched. No public proof of concept exists, the flaw is not on the CISA KEV list, and no exploitation has been reported; Apple shipped the fix in its September 'Updates Everything' release wave.
What to do: Patch to macOS Sequoia 15.8, macOS Tahoe 26.7, or macOS Golden Gate 27 (or later), which Apple released in its September update wave. Until patched, advise users not to mount or connect to WebDAV servers they do not explicitly trust, and review existing WebDAV mounts in Finder/Connect to Server for anything unexpected. No workaround beyond OS updating is documented, since Apple fixed this by removing the vulnerable code.
Affected
| Apple macOS Sequoia | prior to 15.8 |
| Apple macOS Tahoe | prior to 26.7 |
| Apple macOS Golden Gate | prior to 27 |
Estimated exposure
massOn the order of 100 million+ Macs (any unpatched macOS Sequoia, Tahoe, or Golden Gate system) — Apple's Mac installed base is publicly estimated at well over 100 million active devices, and every Mac on an unfixed version carries the vulnerable WebDAV code, though actual attack surface requires the user to connect to an…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description
An out-of-bounds write issue was addressed by removing the vulnerable code. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. Connecting to a malicious WebDAV server may lead to unexpected app termination.