diff --git a/Common/Data/Encoding/Utf8.cpp b/Common/Data/Encoding/Utf8.cpp
index 3ec3fc6ac6..00e2b70578 100644
--- a/Common/Data/Encoding/Utf8.cpp
+++ b/Common/Data/Encoding/Utf8.cpp
@@ -29,6 +29,7 @@
 
 #include "Common/Data/Encoding/Utf8.h"
 #include "Common/Data/Encoding/Utf16.h"
+#include "Common/Log.h"
 
 // is start of UTF sequence
 inline bool isutf(char c) {
@@ -209,6 +210,7 @@ int u8_charnum(const char *s, int offset)
 /* reads the next utf-8 sequence out of a string, updating an index */
 uint32_t u8_nextchar(const char *s, int *index, size_t size) {
 	uint32_t ch = 0;
+	_dbg_assert_(*index >= 0 && *index < 100000000);
 	int sz = 0;
 	int i = *index;
 	do {
@@ -372,8 +374,6 @@ int u8_is_locale_utf8(const char *locale)
   return 0;
 }
 
-UTF8::UTF8(const char *c) : c_(c), size_((int)strlen(c)), index_(0) {}
-
 bool AnyEmojiInString(std::string_view str, size_t byteCount) {
 	int i = 0;
 	while (i < byteCount) {
diff --git a/Common/Data/Encoding/Utf8.h b/Common/Data/Encoding/Utf8.h
index 87ede82241..61b50cab6d 100644
--- a/Common/Data/Encoding/Utf8.h
+++ b/Common/Data/Encoding/Utf8.h
@@ -39,7 +39,7 @@ class UTF8 {
 public:
 	static const uint32_t INVALID = (uint32_t)-1;
 	// TODO: Try to get rid of this constructor.
-	explicit UTF8(const char *c);
+	explicit UTF8(const char *c) : c_(c), size_((int)strlen(c)), index_(0) {}
 	explicit UTF8(std::string_view view) : c_(view.data()), size_((int)view.size()), index_(0) {}
 	explicit UTF8(std::string_view view, int index) : c_(view.data()), size_((int)view.size()), index_(index) {}
 	bool end() const { return index_ == size_; }
diff --git a/Common/Data/Text/WrapText.cpp b/Common/Data/Text/WrapText.cpp
index 68335db1a9..2cabc24232 100644
--- a/Common/Data/Text/WrapText.cpp
+++ b/Common/Data/Text/WrapText.cpp
@@ -219,7 +219,10 @@ void WordWrapper::Wrap() {
 		}
 
 		// Measure the entire word for kerning purposes.  May not be 100% perfect.
-		float newWordWidth = MeasureWidth(str_.substr(lastIndex_, afterIndex - lastIndex_));
+		float newWordWidth = 0.0f;
+		if (afterIndex <= str_.length()) {
+			newWordWidth = MeasureWidth(str_.substr(lastIndex_, afterIndex - lastIndex_));
+		}
 
 		// Is this the end of a word (space)?  We'll also output up to a soft hyphen.
 		if (wordWidth_ > 0.0f && IsSpaceOrShy(c)) {
diff --git a/Common/Render/DrawBuffer.cpp b/Common/Render/DrawBuffer.cpp
index bf646db680..5dc347c0fb 100644
--- a/Common/Render/DrawBuffer.cpp
+++ b/Common/Render/DrawBuffer.cpp
@@ -463,12 +463,15 @@ float AtlasWordWrapper::MeasureWidth(std::string_view str) {
 		uint32_t c = utf.next();
 		if (c == '&') {
 			// Skip ampersand prefixes ("&&" is an ampersand.)
+			if (utf.end()) {
+				break;
+			}
 			c = utf.next();
 		}
 		const AtlasChar *ch = atlasfont_.getChar(c);
-		if (!ch)
+		if (!ch) {
 			ch = atlasfont_.getChar('?');
-
+		}
 		w += ch->wx * scale_;
 	}
 	return w;