diff --git a/api/sanitize_ascii.go b/api/sanitize_ascii.go
index 93ecb4751..aeedaccbf 100644
--- a/api/sanitize_ascii.go
+++ b/api/sanitize_ascii.go
@@ -59,8 +59,7 @@ func (t *sanitizer) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err
 		window := src[nSrc : nSrc+6]
 
 		// Replace C1 Control Characters
-		if window[0] == 0xC2 {
-			repl, _ := mapC1ToCaret(window[:2])
+		if repl, found := mapC1ToCaret(window[:2]); found {
 			if len(repl)+nDst > lDst {
 				err = transform.ErrShortDst
 				return
@@ -74,9 +73,8 @@ func (t *sanitizer) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err
 		}
 
 		// Replace C0 Control Characters
-		if bytes.HasPrefix(window, []byte(`\u00`)) {
-			repl, found := mapC0ToCaret(window)
-			if t.addEscape && found {
+		if repl, found := mapC0ToCaret(window); found {
+			if t.addEscape {
 				repl = append([]byte{'\\'}, repl...)
 			}
 			if len(repl)+nDst > lDst {
@@ -129,6 +127,12 @@ func (t *sanitizer) Reset() {
 
 // mapC0ToCaret maps C0 control sequences to caret notation.
 func mapC0ToCaret(b []byte) ([]byte, bool) {
+	if len(b) != 6 {
+		return b, false
+	}
+	if !bytes.HasPrefix(b, []byte(`\u00`)) {
+		return b, false
+	}
 	m := map[string]string{
 		`\u0000`: `^@`,
 		`\u0001`: `^A`,
diff --git a/api/sanitize_ascii_test.go b/api/sanitize_ascii_test.go
index 9f5c37059..96fdfd073 100644
--- a/api/sanitize_ascii_test.go
+++ b/api/sanitize_ascii_test.go
@@ -22,7 +22,7 @@ func TestHTTPClientSanitizeASCIIControlCharactersC0(t *testing.T) {
 			Author: Author{
 				ID:    "1",
 				Name:  "10\u0010 11\u0011 12\u0012 13\u0013 14\u0014 15\u0015 16\u0016 17\u0017 18\u0018 19\u0019 1A\u001a 1B\u001b 1C\u001c 1D\u001d 1E\u001e 1F\u001f",
-				Login: "monalisa",
+				Login: "monalisa \\u00\u001b",
 			},
 			ActiveLockReason: "Escaped \u001B \\u001B \\\u001B \\\\u001B",
 		}
@@ -47,7 +47,7 @@ func TestHTTPClientSanitizeASCIIControlCharactersC0(t *testing.T) {
 	assert.Equal(t, "^[[31mRed Title^[[0m", issue.Title)
 	assert.Equal(t, "1^A 2^B 3^C 4^D 5^E 6^F 7^G 8^H 9\t A\r\n B^K C^L D\r\n E^N F^O", issue.Body)
 	assert.Equal(t, "10^P 11^Q 12^R 13^S 14^T 15^U 16^V 17^W 18^X 19^Y 1A^Z 1B^[ 1C^\\ 1D^] 1E^^ 1F^_", issue.Author.Name)
-	assert.Equal(t, "monalisa", issue.Author.Login)
+	assert.Equal(t, "monalisa \\u00^[", issue.Author.Login)
 	assert.Equal(t, "Escaped ^[ \\^[ \\^[ \\\\^[", issue.ActiveLockReason)
 }