In APNSwift 1.0.0, calling APNSwiftSigner.sign(digest:) is likely to result in a heap buffer overflow. This has been fixed in 1.0.1.
https://github.com/kylebrowning/APNSwift/security/advisories/GHSA-qh2w-vjxg-mjcg
https://github.com/kylebrowning/APNSwift/pull/32
https://github.com/kylebrowning/APNSwift/issues/31
https://github.com/kylebrowning/APNSwift/commit/97fa7f69dcdd89168fff84e0ba8f999881ee3d3f