diff --git a/src/regexp/all_test.go b/src/regexp/all_test.go
index d78ae6a4cd..9448f60624 100644
--- a/src/regexp/all_test.go
+++ b/src/regexp/all_test.go
@@ -201,6 +201,12 @@ var replaceTests = []ReplaceTest{
 	// Substitution when subexpression isn't found
 	{"(x)?", "$1", "123", "123"},
 	{"abc", "$1", "123", "123"},
+
+	// Substitutions involving a (x){0}
+	{"(a)(b){0}(c)", ".$1|$3.", "xacxacx", "x.a|c.x.a|c.x"},
+	{"(a)(((b))){0}c", ".$1.", "xacxacx", "x.a.x.a.x"},
+	{"((a(b){0}){3}){5}(h)", "y caramb$2", "say aaaaaaaaaaaaaaaah", "say ay caramba"},
+	{"((a(b){0}){3}){5}h", "y caramb$2", "say aaaaaaaaaaaaaaaah", "say ay caramba"},
 }
 
 var replaceLiteralTests = []ReplaceTest{
diff --git a/src/regexp/regexp.go b/src/regexp/regexp.go
index 4e4b41242a..85c070eaeb 100644
--- a/src/regexp/regexp.go
+++ b/src/regexp/regexp.go
@@ -482,6 +482,10 @@ func (re *Regexp) replaceAll(bsrc []byte, src string, nmatch int, repl func(dst
 	} else {
 		endPos = len(src)
 	}
+	if nmatch > re.prog.NumCap {
+		nmatch = re.prog.NumCap
+	}
+
 	for searchPos <= endPos {
 		a := re.doExecute(nil, bsrc, src, searchPos, nmatch)
 		if len(a) == 0 {