diff --git a/src/core/evaluator.js b/src/core/evaluator.js
index 1257a02eb2fca..5e794a66b6b9c 100644
--- a/src/core/evaluator.js
+++ b/src/core/evaluator.js
@@ -1062,7 +1062,13 @@ class PartialEvaluator {
 
     var fontCapability = createPromiseCapability();
 
-    var preEvaluatedFont = this.preEvaluateFont(font);
+    let preEvaluatedFont;
+    try {
+      preEvaluatedFont = this.preEvaluateFont(font);
+    } catch (reason) {
+      warn(`loadFont - ignoring preEvaluateFont errors: "${reason}".`);
+      return errorFont();
+    }
     const { descriptor, hash } = preEvaluatedFont;
 
     var fontRefIsRef = isRef(fontRef),
@@ -3258,6 +3264,9 @@ class PartialEvaluator {
       }
       dict = Array.isArray(df) ? this.xref.fetchIfRef(df[0]) : df;
 
+      if (!(dict instanceof Dict)) {
+        throw new FormatError("Descendant font is not a dictionary.");
+      }
       type = dict.get("Subtype");
       if (!isName(type)) {
         throw new FormatError("invalid font Subtype");
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index b81f2b0f68541..6e52ba6968159 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -70,6 +70,7 @@
 !issue8570.pdf
 !issue8697.pdf
 !issue8702.pdf
+!issue12823.pdf
 !issue8707.pdf
 !issue8798r.pdf
 !issue8823.pdf
diff --git a/test/pdfs/issue12823.pdf b/test/pdfs/issue12823.pdf
new file mode 100644
index 0000000000000..ac70a1711fe45
Binary files /dev/null and b/test/pdfs/issue12823.pdf differ
diff --git a/test/test_manifest.json b/test/test_manifest.json
index a6c608ff0d08d..8ef927167c0c9 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -1163,6 +1163,12 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue12823",
+       "file": "pdfs/issue12823.pdf",
+       "md5": "8391c63006ccc4b41c95de5e8c38deeb",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "bug1050040",
        "file": "pdfs/bug1050040.pdf",
        "md5": "9076b29bd157e2646b457f29a4472a07",