Fix cupsJSONImportXxx long number error handling.

Author: michaelrsweet

CHANGES.md

@@ -6,6 +6,7 @@ v3.0.3 - YYYY-MM-DD
 
 - Now run `ldconfig` on Linux after installing the shared library (Issue #148)
 - Fixed a potential buffer overflow in `cupsFormEncode`.
+- Fixed long number string error handling in `cupsJSONImportXxx`.
 
 
 v3.0.2 - 2026-06-05

cups/json.c

@@ -977,6 +977,9 @@ cupsJSONImportString(const char *s)	// I - JSON string
         goto error;
 
       current->value.number = _cupsStrScand(s, (char **)&s, loc);
+      if (!s)
+        goto error;
+
       count ++;
       prev = current;