diff --git a/src/core/lib/Decimal.mjs b/src/core/lib/Decimal.mjs
index a140fd4e6d..9af54541c8 100644
--- a/src/core/lib/Decimal.mjs
+++ b/src/core/lib/Decimal.mjs
@@ -24,12 +24,17 @@ import Utils from "../Utils.mjs";
  * fromDecimal("10:20:30", "Colon");
  */
 export function fromDecimal(data, delim="Auto") {
-    delim = Utils.charRep(delim);
-    const output = [];
-    let byteStr = data.split(delim);
-    if (byteStr[byteStr.length-1] === "")
-        byteStr = byteStr.slice(0, byteStr.length-1);
+    let byteStr;
+    if (delim === "Auto") {
+        byteStr = data.split(/[^\d-]+/).filter(v => v !== "");
+    } else {
+        const delimStr = Utils.charRep(delim);
+        byteStr = data.split(delimStr);
+        if (byteStr[byteStr.length-1] === "")
+            byteStr = byteStr.slice(0, byteStr.length-1);
+    }
 
+    const output = [];
     for (let i = 0; i < byteStr.length; i++) {
         output[i] = parseInt(byteStr[i], 10);
     }
diff --git a/tests/operations/tests/Hash.mjs b/tests/operations/tests/Hash.mjs
index 1ffb749c05..a805b94fd5 100644
--- a/tests/operations/tests/Hash.mjs
+++ b/tests/operations/tests/Hash.mjs
@@ -722,6 +722,39 @@ TestRegister.addTests([
             }
         ]
     },
+    {
+        name: "HMAC: Decimal key space-delimited matches Latin1 key (fromDecimal Auto delimiter regression)",
+        input: "Hello, World!",
+        expectedOutput: "9b641a008211bb0464a10899d5b37a24ab08ffcf839f5e74d17d99f856530957",
+        recipeConfig: [
+            {
+                "op": "HMAC",
+                "args": [{"option": "Decimal", "string": "65 65"}, "SHA256"]
+            }
+        ]
+    },
+    {
+        name: "HMAC: Latin1 key matches space-delimited Decimal key (fromDecimal Auto delimiter regression)",
+        input: "Hello, World!",
+        expectedOutput: "9b641a008211bb0464a10899d5b37a24ab08ffcf839f5e74d17d99f856530957",
+        recipeConfig: [
+            {
+                "op": "HMAC",
+                "args": [{"option": "Latin1", "string": "AA"}, "SHA256"]
+            }
+        ]
+    },
+    {
+        name: "HMAC: Decimal key comma-delimited matches Latin1 key (fromDecimal Auto delimiter regression)",
+        input: "Hello, World!",
+        expectedOutput: "9b641a008211bb0464a10899d5b37a24ab08ffcf839f5e74d17d99f856530957",
+        recipeConfig: [
+            {
+                "op": "HMAC",
+                "args": [{"option": "Decimal", "string": "65,65"}, "SHA256"]
+            }
+        ]
+    },
     {
         name: "MD5: Complex bytes",
         input: "10dc10e32010de10d010dc10d810d910d010e12e",