[OE-core] [scarthgap] [PATCH] Fix CVE CVSS scoring to use maximum score from all sources

["Het Patel -X (hetpat - E INFOCHIPS PRIVATE LIMITED at Cisco)" <hetpat@cisco.com>]

From: Het Patel <hetpat@cisco.com>

The CVE check system was incorrectly reporting lower CVSS scores when
multiple scoring sources were available in the NVD database. This
occurred because the code only extracted the first element from the
CVSSv2, CVSSv3, and CVSSv4 metrics arrays, which could be a Secondary
source with a lower score instead of the Primary source with the
actual severity score.

This fix takes maximum CVSS score.

Signed-off-by: Het Patel <hetpat@cisco.com>
---
 .../meta/cve-update-nvd2-native.bb            | 55 +++++++++++++------
 1 file changed, 39 insertions(+), 16 deletions(-)

diff --git a/meta/recipes-core/meta/cve-update-nvd2-native.bb b/meta/recipes-core/meta/cve-update-nvd2-native.bb
index 945bd1d927..28d5810d5d 100644
--- a/meta/recipes-core/meta/cve-update-nvd2-native.bb
+++ b/meta/recipes-core/meta/cve-update-nvd2-native.bb
@@ -352,32 +352,55 @@ def update_db(conn, elt):
         if desc['lang'] == 'en':
             cveDesc = desc['value']
     date = elt['cve']['lastModified']
+
+    # Extract maximum CVSS scores from all sources (Primary and Secondary)
+    cvssv2 = 0.0
     try:
-        accessVector = elt['cve']['metrics']['cvssMetricV2'][0]['cvssData']['accessVector']
-        vectorString = elt['cve']['metrics']['cvssMetricV2'][0]['cvssData']['vectorString']
-        cvssv2 = elt['cve']['metrics']['cvssMetricV2'][0]['cvssData']['baseScore']
+        # Iterate through all cvssMetricV2 entries and find the maximum score
+        for metric in elt['cve']['metrics']['cvssMetricV2']:
+            score = metric['cvssData']['baseScore']
+            if score > cvssv2:
+                cvssv2 = score
+                accessVector = metric['cvssData']['accessVector']
+                vectorString = metric['cvssData']['vectorString']
     except KeyError:
-        cvssv2 = 0.0
-    cvssv3 = None
+        pass
+
+    cvssv3 = 0.0
     try:
-        accessVector = accessVector or elt['cve']['metrics']['cvssMetricV30'][0]['cvssData']['attackVector']
-        vectorString = vectorString or elt['cve']['metrics']['cvssMetricV30'][0]['cvssData']['vectorString']
-        cvssv3 = elt['cve']['metrics']['cvssMetricV30'][0]['cvssData']['baseScore']
+        # Iterate through all cvssMetricV30 entries and find the maximum score
+        for metric in elt['cve']['metrics']['cvssMetricV30']:
+            score = metric['cvssData']['baseScore']
+            if score > cvssv3:
+                cvssv3 = score
+                accessVector = accessVector or metric['cvssData']['attackVector']
+                vectorString = vectorString or metric['cvssData']['vectorString']
     except KeyError:
         pass
+
     try:
-        accessVector = accessVector or elt['cve']['metrics']['cvssMetricV31'][0]['cvssData']['attackVector']
-        vectorString = vectorString or elt['cve']['metrics']['cvssMetricV31'][0]['cvssData']['vectorString']
-        cvssv3 = cvssv3 or elt['cve']['metrics']['cvssMetricV31'][0]['cvssData']['baseScore']
+        # Iterate through all cvssMetricV31 entries and find the maximum score
+        for metric in elt['cve']['metrics']['cvssMetricV31']:
+            score = metric['cvssData']['baseScore']
+            if score > cvssv3:
+                cvssv3 = score
+                accessVector = accessVector or metric['cvssData']['attackVector']
+                vectorString = vectorString or metric['cvssData']['vectorString']
     except KeyError:
         pass
-    cvssv3 = cvssv3 or 0.0
+
+    cvssv4 = 0.0
     try:
-        accessVector = accessVector or elt['cve']['metrics']['cvssMetricV40'][0]['cvssData']['attackVector']
-        vectorString = vectorString or elt['cve']['metrics']['cvssMetricV40'][0]['cvssData']['vectorString']
-        cvssv4 = elt['cve']['metrics']['cvssMetricV40'][0]['cvssData']['baseScore']
+        # Iterate through all cvssMetricV40 entries and find the maximum score
+        for metric in elt['cve']['metrics']['cvssMetricV40']:
+            score = metric['cvssData']['baseScore']
+            if score > cvssv4:
+                cvssv4 = score
+                accessVector = accessVector or metric['cvssData']['attackVector']
+                vectorString = vectorString or metric['cvssData']['vectorString']
     except KeyError:
-        cvssv4 = 0.0
+        pass
+
     accessVector = accessVector or "UNKNOWN"
     vectorString = vectorString or "UNKNOWN"