GitHub sets CodeQL scan limits for macOS 27, Xcode 27 and Swift 6.4
GitHub announced CodeQL compatibility limits on October 19 for macOS 27, Xcode 27 and Swift 6.4. It attributes the changes to Apple no longer including Intel code in some system binaries and libraries that CodeQL uses to trace builds.
With Xcode 27 installed, traced extraction is unavailable for C/C++, C#, Go, Java, Kotlin and Swift. For macOS 27, GitHub says traced extraction may be unavailable for those languages. The distinction matters: the announcement does not say every kind of CodeQL scan stops working on the new operating system.
Swift 6.4 is not supported by CodeQL on any platform. Separately, GitHub says support for Intel-based Macs will be deprecated in mid-December 2026. The announced future deprecation is not the same as saying Intel Mac support already ended in October.
For Swift scans and traced builds in other languages, GitHub recommends pinning workflows to macOS 26 or earlier and Xcode 26 or earlier. GitHub Actions users should pin the runner image and toolchain rather than relying on the latest versions.
For C/C++, C# and Java, GitHub identifies build mode none as an alternative that does not require tracing a build. Its announcement does not extend that workaround to every affected language, so teams should not assume it solves the Swift or Go limitations.
For teams maintaining automated code-review and security workflows, the immediate issue is whether the selected scan mode and toolchain remain supported. A successful application build is not proof that CodeQL extracted and analyzed the intended code. Review scan results when changing runner images or Xcode versions, and distinguish compatibility failures from a clean security result.