diff --git a/src/internal/fuzz/mutator.go b/src/internal/fuzz/mutator.go
index 9aa56782b0..da7200dcbe 100644
--- a/src/internal/fuzz/mutator.go
+++ b/src/internal/fuzz/mutator.go
@@ -106,12 +106,7 @@ func (m *mutator) mutate(vals []interface{}, maxBytes int) {
 			copy(m.scratch, v)
 		}
 		m.mutateBytes(&m.scratch)
-		var s string
-		shdr := (*reflect.StringHeader)(unsafe.Pointer(&s))
-		bhdr := (*reflect.SliceHeader)(unsafe.Pointer(&m.scratch))
-		shdr.Data = bhdr.Data
-		shdr.Len = bhdr.Len
-		vals[i] = s
+		vals[i] = string(m.scratch)
 	case []byte:
 		if len(v) > maxPerVal {
 			panic(fmt.Sprintf("cannot mutate bytes of length %d", len(v)))
diff --git a/src/internal/fuzz/mutator_test.go b/src/internal/fuzz/mutator_test.go
index ee2912dfd2..d8015ce213 100644
--- a/src/internal/fuzz/mutator_test.go
+++ b/src/internal/fuzz/mutator_test.go
@@ -5,6 +5,7 @@
 package fuzz
 
 import (
+	"bytes"
 	"fmt"
 	"os"
 	"strconv"
@@ -99,3 +100,18 @@ func BenchmarkMutatorAllBasicTypes(b *testing.B) {
 		})
 	}
 }
+
+func TestStringImmutability(t *testing.T) {
+	v := []interface{}{"hello"}
+	m := newMutator()
+	m.mutate(v, 1024)
+	original := v[0].(string)
+	originalCopy := make([]byte, len(original))
+	copy(originalCopy, []byte(original))
+	for i := 0; i < 25; i++ {
+		m.mutate(v, 1024)
+	}
+	if !bytes.Equal([]byte(original), originalCopy) {
+		t.Fatalf("string was mutated: got %x, want %x", []byte(original), originalCopy)
+	}
+}
diff --git a/src/testing/fuzz.go b/src/testing/fuzz.go
index 57ea418039..ddce065783 100644
--- a/src/testing/fuzz.go
+++ b/src/testing/fuzz.go
@@ -293,7 +293,10 @@ var supportedTypes = map[reflect.Type]bool{
 // f.Fuzz(func(t *testing.T, b []byte, i int) { ... })
 //
 // This function should be fast, deterministic, and stateless.
-// None of the pointers to any input data should be retained between executions.
+//
+// No mutatable input arguments, or pointers to them, should be retained between
+// executions of the fuzz function, as the memory backing them may be mutated
+// during a subsequent invocation.
 //
 // This is a terminal function which will terminate the currently running fuzz
 // target by calling runtime.Goexit.