Another rounding fix

cvss/__init__.py

@@ -8,4 +8,4 @@
 from .exceptions import CVSS2Error, CVSS3Error, CVSS4Error, CVSSError
 from .interactive import ask_interactively
 
-__version__ = "3.2"
+__version__ = "3.3"

cvss/cvss4.py

@@ -52,8 +52,19 @@
 from .exceptions import CVSS4MalformedError, CVSS4MandatoryError
 
 
-def round_away_from_zero(x):
-    return float(D(x * 10).quantize(D("1"), rounding=ROUND_HALF_UP) / 10)
+def final_rounding(x):
+    """
+    Round to one decimal place. Use Decimal because Python float rounding defaults to
+    "round half to even". We actually want "round half away from zero" aka "round half up" for
+    positive numbers.
+
+    Make sure that values like the following are correctly rounded despite floating point
+    inaccuracies:
+
+    8.6 - 7.15 = 1.4499999999999993 (float) => 1.5
+    """
+    pre_rounded = D(x).quantize(D("0.00001"), rounding=ROUND_HALF_UP)
+    return float(D(pre_rounded).quantize(D("0.1"), rounding=ROUND_HALF_UP))
 
 
 class CVSS4(object):
@@ -547,7 +558,7 @@ def compute_base_score(self):
         value = max(0.0, value)
         value = min(10.0, value)
 
-        self.base_score = round_away_from_zero(value)
+        self.base_score = final_rounding(value)
 
     def clean_vector(self, output_prefix=True):
         """