diff --git a/security/manager/ssl/src/nsNTLMAuthModule.cpp b/security/manager/ssl/src/nsNTLMAuthModule.cpp
index 4ce206a8d0f7..9971e4d6c99a 100644
--- a/security/manager/ssl/src/nsNTLMAuthModule.cpp
+++ b/security/manager/ssl/src/nsNTLMAuthModule.cpp
@@ -591,7 +591,8 @@ GenerateType3Msg(const nsString &domain,
     ucsDomainBuf = domain;
     domainPtr = ucsDomainBuf.get();
     domainLen = ucsDomainBuf.Length() * 2;
-    WriteUnicodeLE((void *) domainPtr, (const PRUnichar *) domainPtr, domainLen);
+    WriteUnicodeLE((void *) domainPtr, (const PRUnichar *) domainPtr,
+                   ucsDomainBuf.Length());
 #else
     domainPtr = domain.get();
     domainLen = domain.Length() * 2;
@@ -613,7 +614,8 @@ GenerateType3Msg(const nsString &domain,
     ucsUserBuf = username;
     userPtr = ucsUserBuf.get();
     userLen = ucsUserBuf.Length() * 2;
-    WriteUnicodeLE((void *) userPtr, (const PRUnichar *) userPtr, userLen);
+    WriteUnicodeLE((void *) userPtr, (const PRUnichar *) userPtr,
+                   ucsUserBuf.Length());
 #else
     userPtr = username.get();
     userLen = username.Length() * 2;
@@ -640,7 +642,8 @@ GenerateType3Msg(const nsString &domain,
     hostPtr = ucsHostBuf.get();
     hostLen = ucsHostBuf.Length() * 2;
 #ifdef IS_BIG_ENDIAN
-    WriteUnicodeLE((void *) hostPtr, (const PRUnichar *) hostPtr, hostLen);
+    WriteUnicodeLE((void *) hostPtr, (const PRUnichar *) hostPtr,
+                   ucsHostBuf.Length());
 #endif
   }
   else