diff --git a/security/manager/ssl/src/nsIdentityChecking.cpp b/security/manager/ssl/src/nsIdentityChecking.cpp
index 098689075e6..f2a25d130dc 100644
--- a/security/manager/ssl/src/nsIdentityChecking.cpp
+++ b/security/manager/ssl/src/nsIdentityChecking.cpp
@@ -841,6 +841,7 @@ nsNSSComponent::IdentityInfoInit()
     NS_ASSERTION(rv==SECSuccess, "error converting ascii to binary.");
     rv = ATOB_ConvertAsciiToItem(&ias.serialNumber, const_cast<char*>(entry.serial_base64));
     NS_ASSERTION(rv==SECSuccess, "error converting ascii to binary.");
+    ias.serialNumber.type = siUnsignedInteger;
 
     entry.cert = CERT_FindCertByIssuerAndSN(nsnull, &ias);
     NS_ASSERTION(entry.cert, "Could not find EV root in NSS storage");