diff --git a/src/internal.c b/src/internal.c
index 8a72a675d8..3c8822bec2 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -1270,7 +1270,8 @@ static int ImportKeyState(WOLFSSL* ssl, const byte* exp, word32 len, byte ver,
     }
 
     sz = exp[idx++];
-    if (sz > sizeof(keys->client_write_IV) || (sz * 2) + idx > len) {
+    if (sz > sizeof(keys->client_write_IV) ||
+            (sz * 2) + idx + AEAD_MAX_EXP_SZ + OPAQUE8_LEN > len) {
         WOLFSSL_MSG("Buffer not large enough for write IV import");
         return BUFFER_E;
     }
@@ -16898,10 +16899,15 @@ int ProcessPeerCerts(WOLFSSL* ssl, byte* input, word32* inOutIdx,
                         ret = KEYUSE_ENCIPHER_E;
                         WOLFSSL_ERROR_VERBOSE(ret);
                     }
-                    if ((ssl->specs.kea != rsa_kea) &&
-                        (ssl->specs.sig_algo == rsa_sa_algo ||
-                            (ssl->specs.sig_algo == ecc_dsa_sa_algo &&
-                                 !ssl->specs.static_ecdh)) &&
+                    /* TLS 1.3 decouples sig algorithm from cipher suite, so
+                     * specs.sig_algo is any_sa_algo. RFC 8446 4.4.2.4 still
+                     * requires digital_signature when keyUsage is present on
+                     * the cert that drives CertificateVerify. */
+                    if (((ssl->specs.kea != rsa_kea) &&
+                            (IsAtLeastTLSv1_3(ssl->version) ||
+                             ssl->specs.sig_algo == rsa_sa_algo ||
+                                (ssl->specs.sig_algo == ecc_dsa_sa_algo &&
+                                     !ssl->specs.static_ecdh))) &&
                         (args->dCert->extKeyUsage & KEYUSE_DIGITAL_SIG) == 0) {
                         WOLFSSL_MSG("KeyUse Digital Sig not set");
                         ret = KEYUSE_SIGNATURE_E;
@@ -24240,6 +24246,8 @@ static int BuildMD5_CertVerify(const WOLFSSL* ssl, byte* digest)
 #ifdef WOLFSSL_SMALL_STACK
     wc_Md5* md5 = (wc_Md5*)XMALLOC(sizeof(wc_Md5), ssl->heap,
         DYNAMIC_TYPE_HASHCTX);
+    if (md5 == NULL)
+        return MEMORY_E;
 #else
     wc_Md5  md5[1];
 #endif
@@ -24284,6 +24292,8 @@ static int BuildSHA_CertVerify(const WOLFSSL* ssl, byte* digest)
 #ifdef WOLFSSL_SMALL_STACK
     wc_Sha* sha = (wc_Sha*)XMALLOC(sizeof(wc_Sha), ssl->heap,
         DYNAMIC_TYPE_HASHCTX);
+    if (sha == NULL)
+        return MEMORY_E;
 #else
     wc_Sha  sha[1];
 #endif
diff --git a/src/tls.c b/src/tls.c
index 347761b263..506a7c17a8 100644
--- a/src/tls.c
+++ b/src/tls.c
@@ -9291,6 +9291,14 @@ static int TLSX_KeyShare_ProcessDh(WOLFSSL* ssl, KeyShareEntry* keyShareEntry)
     }
 #endif
 
+    /* RFC 8446 Section 4.2.8.1: FFDHE key_exchange values are left-padded with
+     * zeros to the size of the named-group prime. Reject any peer key share
+     * whose byte length does not match the expected prime size. */
+    if (keyShareEntry->keLen != pSz) {
+        WOLFSSL_ERROR_VERBOSE(PEER_KEY_ERROR);
+        return PEER_KEY_ERROR;
+    }
+
     /* if DhKey is not setup, do it now */
     if (keyShareEntry->key == NULL) {
         keyShareEntry->key = (DhKey*)XMALLOC(sizeof(DhKey), ssl->heap,