diff --git a/src/crypto/x509/internal/macos/corefoundation.go b/src/crypto/x509/internal/macos/corefoundation.go
index d1295daee1..b27a9172e1 100644
--- a/src/crypto/x509/internal/macos/corefoundation.go
+++ b/src/crypto/x509/internal/macos/corefoundation.go
@@ -30,7 +30,7 @@ type CFRef uintptr
 func CFDataToSlice(data CFRef) []byte {
 	length := CFDataGetLength(data)
 	ptr := CFDataGetBytePtr(data)
-	src := (*[1 << 20]byte)(unsafe.Pointer(ptr))[:length:length]
+	src := unsafe.Slice((*byte)(unsafe.Pointer(ptr)), length)
 	out := make([]byte, length)
 	copy(out, src)
 	return out
diff --git a/src/crypto/x509/root_windows.go b/src/crypto/x509/root_windows.go
index d65d8768d9..5515c439c7 100644
--- a/src/crypto/x509/root_windows.go
+++ b/src/crypto/x509/root_windows.go
@@ -69,13 +69,13 @@ func extractSimpleChain(simpleChain **syscall.CertSimpleChain, count int) (chain
 		return nil, errors.New("x509: invalid simple chain")
 	}
 
-	simpleChains := (*[1 << 20]*syscall.CertSimpleChain)(unsafe.Pointer(simpleChain))[:count:count]
+	simpleChains := unsafe.Slice(simpleChain, count)
 	lastChain := simpleChains[count-1]
-	elements := (*[1 << 20]*syscall.CertChainElement)(unsafe.Pointer(lastChain.Elements))[:lastChain.NumElements:lastChain.NumElements]
+	elements := unsafe.Slice(lastChain.Elements, lastChain.NumElements)
 	for i := 0; i < int(lastChain.NumElements); i++ {
 		// Copy the buf, since ParseCertificate does not create its own copy.
 		cert := elements[i].CertContext
-		encodedCert := (*[1 << 20]byte)(unsafe.Pointer(cert.EncodedCert))[:cert.Length:cert.Length]
+		encodedCert := unsafe.Slice(cert.EncodedCert, cert.Length)
 		buf := make([]byte, cert.Length)
 		copy(buf, encodedCert)
 		parsedCert, err := ParseCertificate(buf)
@@ -258,8 +258,7 @@ func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate
 	}
 
 	if lqCtxCount := topCtx.LowerQualityChainCount; lqCtxCount > 0 {
-		lqCtxs := (*[1 << 20]*syscall.CertChainContext)(unsafe.Pointer(topCtx.LowerQualityChains))[:lqCtxCount:lqCtxCount]
-
+		lqCtxs := unsafe.Slice(topCtx.LowerQualityChains, lqCtxCount)
 		for _, ctx := range lqCtxs {
 			chain, err := verifyChain(c, ctx, opts)
 			if err == nil {