diff --git a/src/native/libs/System.Security.Cryptography.Native/pal_ssl.c b/src/native/libs/System.Security.Cryptography.Native/pal_ssl.c
index 811e2cc2a64d9d..d94c4516944483 100644
--- a/src/native/libs/System.Security.Cryptography.Native/pal_ssl.c
+++ b/src/native/libs/System.Security.Cryptography.Native/pal_ssl.c
@@ -1053,7 +1053,13 @@ int32_t CryptoNative_SslAddExtraChainCert(SSL* ssl, X509* x509)
         return 0;
     }
 
-    if (SSL_ctrl(ssl, SSL_CTRL_CHAIN_CERT, 1,(void*)x509) == 1)
+    // larg must be 0 (SSL_add0_chain_cert), not 1 (SSL_add1_chain_cert). The caller,
+    // Interop.Ssl.AddExtraChainCertificates, up-refs and then calls SetHandleAsInvalid to
+    // hand its reference over, which is the add0 contract and matches
+    // CryptoNative_SslCtxAddExtraChainCert above. With add1 libssl takes a reference of its
+    // own and the caller's is abandoned rather than released, leaking one X509 per
+    // intermediate per SSL handle.
+    if (SSL_ctrl(ssl, SSL_CTRL_CHAIN_CERT, 0,(void*)x509) == 1)
     {
         return 1;
     }