GitHub's changelog notes that starting with macOS 27 and Xcode 27, Apple no longer includes Intel x86_64 code in some system binaries and libraries used by CodeQL to trace builds, which helps explain why traced scans aren’t supported on these versions.
The same changelog notes that CodeQL doesn’t support Swift 6.4 on any platform.
CONCRETE IMPLICATIONS FOR LANGUAGES AND RUNTIMES
Xcode 27 blocks traced extraction for C/C++, C#, Go, Java, Kotlin, and Swift.
macOS 27 may also block traced extraction for these languages.
Swift 6.4 is not supported by CodeQL on any platform.
RECOMMENDED WORKFLOW CHANGES AND MITIGATIONS
Intel-based Mac support is scheduled to be deprecated in mid-December 2026, guiding teams to consider alternatives or updated hardware/CI strategies.
If scanning Swift or using traced builds for other languages, pin your workflows to macOS 26 or earlier and Xcode 26 or earlier.
In GitHub Actions, pin the runner image and toolchain in your workflow rather than relying on the latest versions.
For C/C++, C#, and Java, you can switch to build mode none, which doesn’t require tracing a build.
- Pin to macOS 26 or earlier and Xcode 26 or earlier when feasible.
- Pin runner images and toolchains in GitHub Actions workflows to avoid relying on the latest builds.
RELATED COVERAGE
- Xcode 27 runner image GA on GitHub Actions: arm64-only macOS runners with one-Xcode-version-per-image
- GitHub completes staged rollout of stateless App installation tokens, with longer token format and unchanged permissions
- GitHub Copilot adds general availability for local sandboxing across CLI, app, and VS Code
- GitHub adds confidential comments to repository security advisories
- Developer Tools articles
SOURCES
- Archive: 2026 - GitHub Changelog: CodeQL changes for macOS 27, Xcode 27, and Swift 6.4 Published · Primary source
