*next = NULL;
                        return arg;
                case '\\':
-                       c = *++src;
-                       if (need_bs_quote(c) && *++src == '\'') {
-                               *dst++ = c;
+                       /*
+                        * Allow backslashed characters outside of
+                        * single-quotes only if they need escaping,
+                        * and only if we resume the single-quoted part
+                        * afterward.
+                        */
+                       if (need_bs_quote(src[1]) && src[2] == '\'') {
+                               *dst++ = src[1];
+                               src += 2;
                                continue;
                        }
                /* Fallthrough */