diff --git a/src/core/chunked_stream.js b/src/core/chunked_stream.js
index f58aa53bd..88663af8b 100644
--- a/src/core/chunked_stream.js
+++ b/src/core/chunked_stream.js
@@ -213,7 +213,9 @@ class ChunkedStream {
 
   peekByte() {
     const peekedByte = this.getByte();
-    this.pos--;
+    if (peekedByte !== -1) {
+      this.pos--;
+    }
     return peekedByte;
   }
 
diff --git a/src/core/stream.js b/src/core/stream.js
index 1867c8c99..1b085a629 100644
--- a/src/core/stream.js
+++ b/src/core/stream.js
@@ -86,7 +86,9 @@ var Stream = (function StreamClosure() {
     },
     peekByte: function Stream_peekByte() {
       var peekedByte = this.getByte();
-      this.pos--;
+      if (peekedByte !== -1) {
+        this.pos--;
+      }
       return peekedByte;
     },
     peekBytes(length, forceClamped = false) {
@@ -234,7 +236,9 @@ var DecodeStream = (function DecodeStreamClosure() {
     },
     peekByte: function DecodeStream_peekByte() {
       var peekedByte = this.getByte();
-      this.pos--;
+      if (peekedByte !== -1) {
+        this.pos--;
+      }
       return peekedByte;
     },
     peekBytes(length, forceClamped = false) {