src/encoding/pem/pem.go      | 7 +++++--
 src/encoding/pem/pem_test.go | 4 ++++

diff --git a/src/encoding/pem/pem.go b/src/encoding/pem/pem.go
index 2356096ade24d2fe9b5821f983c191f04710f6e5..6bf2b41ad0eb7faf0df50b09f02e8b0761447d68 100644
--- a/src/encoding/pem/pem.go
+++ b/src/encoding/pem/pem.go
@@ -95,6 +95,9 @@ 	endTrailerIndex := 0
 	for {
 		// If we've already tried parsing a block, skip past the END we already
 		// saw.
+		if endTrailerIndex < 0 || endTrailerIndex > len(rest) {
+			return nil, data
+		}
 		rest = rest[endTrailerIndex:]
 
 		// Find the first END line, and then find the last BEGIN line before
@@ -116,11 +119,11 @@
 		var typeLine []byte
 		var consumed int
 		typeLine, rest, consumed = getLine(rest)
+		endIndex -= consumed
+		endTrailerIndex -= consumed
 		if !bytes.HasSuffix(typeLine, pemEndOfLine) {
 			continue
 		}
-		endIndex -= consumed
-		endTrailerIndex -= consumed
 		typeLine = typeLine[0 : len(typeLine)-len(pemEndOfLine)]
 
 		p = &Block{
diff --git a/src/encoding/pem/pem_test.go b/src/encoding/pem/pem_test.go
index 5bdc2f66a7b3abb377ec0680b89bfc74e9cccfb1..fa6e8ba62bdb8780c4d2fd1039c1a9ff44284948 100644
--- a/src/encoding/pem/pem_test.go
+++ b/src/encoding/pem/pem_test.go
@@ -736,3 +736,7 @@ 	f.Fuzz(func(t *testing.T, data []byte) {
 		Decode(data)
 	})
 }
+
+func TestMissingEndTrailer(t *testing.T) {
+	Decode([]byte{0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x42, 0x45, 0x47, 0x49, 0x4e, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0xa, 0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x45, 0x4e, 0x44, 0x20})
+}