diff --git a/dnscrypt/dnscrypt.c b/dnscrypt/dnscrypt.c
index 2b38a1cdb..72a9527f5 100644
--- a/dnscrypt/dnscrypt.c
+++ b/dnscrypt/dnscrypt.c
@@ -732,6 +732,11 @@ dnsc_load_local_data(struct dnsc_env* dnscenv, struct config_file *cfg)
             );
             continue;
         }
+	if((unsigned)strlen(dnscenv->provider_name) >= (unsigned)0xffff0000) {
+		/* guard against integer overflow in rrlen calculation */
+		verbose(VERB_OPS, "cert #%" PRIu32 " is too long", serial);
+		continue
+	}
         rrlen = strlen(dnscenv->provider_name) +
                          strlen(ttl_class_type) +
                          4 * sizeof(struct SignedCert) + // worst case scenario
diff --git a/doc/Changelog b/doc/Changelog
index 9803ae8cc..7398075e1 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -9,6 +9,8 @@
 	  and ipsecmod_new(), reported by X41 D-Sec.
 	- Fix Out-of-bounds Read in rr_comment_dnskey(),
 	  reported by X41 D-Sec.
+	- Fix Integer Overflows in Size Calculations,
+	  reported by X41 D-Sec.
 
 18 November 2019: Wouter
 	- In unbound-host use separate variable for get_option to please
diff --git a/respip/respip.c b/respip/respip.c
index 36a1c9726..482762b50 100644
--- a/respip/respip.c
+++ b/respip/respip.c
@@ -479,10 +479,16 @@ copy_rrset(const struct ub_packed_rrset_key* key, struct regional* region)
 	if(!ck->rk.dname)
 		return NULL;
 
+	if((unsigned)data->count >= 0xffff00U)
+		return NULL; /* guard against integer overflow in dsize */
 	dsize = sizeof(struct packed_rrset_data) + data->count *
 		(sizeof(size_t)+sizeof(uint8_t*)+sizeof(time_t));
-	for(i=0; i<data->count; i++)
+	for(i=0; i<data->count; i++) {
+		if((unsigned)dsize >= 0x0fffffffU ||
+			(unsigned)data->rr_len[i] >= 0x0fffffffU)
+			return NULL; /* guard against integer overflow */
 		dsize += data->rr_len[i];
+	}
 	d = regional_alloc(region, dsize);
 	if(!d)
 		return NULL;