diff --git a/src/CertManager.sol b/src/CertManager.sol
index 29ecfd0..c1e2dda 100644
--- a/src/CertManager.sol
+++ b/src/CertManager.sol
@@ -382,7 +382,11 @@ contract CertManager is ICertManager {
             revert InvalidCertAlgorithm();
         }
         // as extensions are used in cert, version should be 3 (value 2) as per https://datatracker.ietf.org/doc/html/rfc5280#section-4.1.2.1
-        if (certificate.uintAt(certificate.firstChildOf(versionPtr)) != 2) revert InvalidCertVersion();
+        Asn1Ptr versionValuePtr = certificate.firstChildOf(versionPtr);
+        if (versionValuePtr.content() + versionValuePtr.length() != versionPtr.content() + versionPtr.length()) {
+            revert Asn1Decode.InvalidAsn1Length();
+        }
+        if (certificate.uintAt(versionValuePtr) != 2) revert InvalidCertVersion();
 
         (notAfter, maxPathLen, issuerHash, subjectHash, pubKey) =
             _parseTbsInner(certificate, sigAlgoPtr, ca, ptr.content() + ptr.length());
diff --git a/test/CertManager.t.sol b/test/CertManager.t.sol
index 6db1293..5bcd42f 100644
--- a/test/CertManager.t.sol
+++ b/test/CertManager.t.sol
@@ -7,6 +7,7 @@ import {ICertManager} from "../src/ICertManager.sol";
 import {Asn1Decode, LibAsn1Ptr, Asn1Ptr} from "../src/Asn1Decode.sol";
 import {LibBytes} from "../src/LibBytes.sol";
 import {P384Verifier} from "../src/P384Verifier.sol";
+import {IP384Verifier} from "../src/IP384Verifier.sol";
 import {P384HintCollector} from "./helpers/HintedNitroTestHelpers.sol";
 
 contract Asn1DecodeHarness {
@@ -52,6 +53,19 @@ contract CertManagerExtensionsHarness is CertManager {
     }
 }
 
+contract RevertingP384Verifier is IP384Verifier {
+    error SignatureVerificationCalled();
+
+    function verifyP384SignatureWithHints(bytes memory, bytes memory, bytes memory, bytes memory)
+        external
+        pure
+        override
+        returns (bool)
+    {
+        revert SignatureVerificationCalled();
+    }
+}
+
 contract CertManagerTest is Test {
     using Asn1Decode for bytes;
     using LibAsn1Ptr for Asn1Ptr;
@@ -166,6 +180,15 @@ contract CertManagerTest is Test {
         cm.verifyCACertWithHints(mutated, keccak256(CB0), "");
     }
 
+    function test_ParseTbsRejectsTrailingVersionWrapperFieldBeforeSignatureVerification() public {
+        vm.warp(1775145600);
+        CertManager cm = new CertManager(new RevertingP384Verifier());
+        bytes memory mutated = _appendVersionTrailingField(CB1);
+
+        vm.expectRevert(Asn1Decode.InvalidAsn1Length.selector);
+        cm.verifyCACertWithHints(mutated, keccak256(CB0), "");
+    }
+
     function test_ParsePubKeyAcceptsUncompressedP384Point() public view {
         bytes memory pubKey = _patternBytes(96);
         bytes memory spki = abi.encodePacked(hex"3076301006072a8648ce3d020106052b8104002203620004", pubKey);
@@ -419,6 +442,19 @@ contract CertManagerTest is Test {
         _writeDerLength(result, tbsPtr, _addDelta(tbsPtr.length(), delta));
     }
 
+    function _appendVersionTrailingField(bytes memory certificate) internal pure returns (bytes memory result) {
+        Asn1Ptr root = certificate.root();
+        Asn1Ptr tbsPtr = certificate.firstChildOf(root);
+        Asn1Ptr versionPtr = certificate.firstChildOf(tbsPtr);
+        bytes memory nullField = hex"0500";
+        int256 delta = int256(nullField.length);
+        result = _insertBytes(certificate, versionPtr.content() + versionPtr.length(), nullField);
+
+        _writeDerLength(result, root, _addDelta(root.length(), delta));
+        _writeDerLength(result, tbsPtr, _addDelta(tbsPtr.length(), delta));
+        _writeDerLength(result, versionPtr, _addDelta(versionPtr.length(), delta));
+    }
+
     function _appendSignatureTrailingField(bytes memory certificate) internal pure returns (bytes memory result) {
         (Asn1Ptr root, Asn1Ptr sigPtr, Asn1Ptr sigRoot,) = _certSignaturePtrs(certificate);
         bytes memory extraInteger = hex"020100";