diff --git a/.changeset/calm-brooms-flow.md b/.changeset/calm-brooms-flow.md
new file mode 100644
index 00000000..55c9c5f4
--- /dev/null
+++ b/.changeset/calm-brooms-flow.md
@@ -0,0 +1,5 @@
+---
+"@pimlico/alto": patch
+---
+
+Version updated till Dec 18
diff --git a/src/utils/userop.ts b/src/utils/userop.ts
index 69fdf852..3347aa19 100644
--- a/src/utils/userop.ts
+++ b/src/utils/userop.ts
@@ -27,6 +27,7 @@ import {
     pad,
     parseAbi,
     parseEventLogs,
+    size,
     slice,
     toHex,
     zeroAddress
@@ -132,11 +133,15 @@ export function unpackPaymasterAndData(paymasterAndData: Hex) {
             paymasterData: null
         }
     }
+
+    const paymasterAndDataSize = size(paymasterAndData)
+
     return {
         paymaster: getAddress(slice(paymasterAndData, 0, 20)),
         paymasterVerificationGasLimit: BigInt(slice(paymasterAndData, 20, 36)),
         paymasterPostOpGasLimit: BigInt(slice(paymasterAndData, 36, 52)),
-        paymasterData: slice(paymasterAndData, 52)
+        paymasterData:
+            paymasterAndDataSize > 52 ? slice(paymasterAndData, 52) : null
     }
 }