diff --git a/src/test/fuzz/CMakeLists.txt b/src/test/fuzz/CMakeLists.txt
--- a/src/test/fuzz/CMakeLists.txt
+++ b/src/test/fuzz/CMakeLists.txt
@@ -80,6 +80,7 @@
 	base_encode_decode
 	block
 	block_header
+	blockfilter
 	bloom_filter
 	rolling_bloom_filter
 	cashaddr
diff --git a/src/test/fuzz/blockfilter.cpp b/src/test/fuzz/blockfilter.cpp
new file mode 100644
--- /dev/null
+++ b/src/test/fuzz/blockfilter.cpp
@@ -0,0 +1,46 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <blockfilter.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <optional>
+#include <string>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t> &buffer) {
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    const std::optional<BlockFilter> block_filter =
+        ConsumeDeserializable<BlockFilter>(fuzzed_data_provider);
+    if (!block_filter) {
+        return;
+    }
+    {
+        (void)block_filter->ComputeHeader(ConsumeUInt256(fuzzed_data_provider));
+        (void)block_filter->GetBlockHash();
+        (void)block_filter->GetEncodedFilter();
+        (void)block_filter->GetHash();
+    }
+    {
+        const BlockFilterType block_filter_type = block_filter->GetFilterType();
+        (void)BlockFilterTypeName(block_filter_type);
+    }
+    {
+        const GCSFilter gcs_filter = block_filter->GetFilter();
+        (void)gcs_filter.GetN();
+        (void)gcs_filter.GetParams();
+        (void)gcs_filter.GetEncoded();
+        (void)gcs_filter.Match(
+            ConsumeRandomLengthByteVector(fuzzed_data_provider));
+        GCSFilter::ElementSet element_set;
+        while (fuzzed_data_provider.ConsumeBool()) {
+            element_set.insert(
+                ConsumeRandomLengthByteVector(fuzzed_data_provider));
+            gcs_filter.MatchAny(element_set);
+        }
+    }
+}
diff --git a/src/test/fuzz/integer.cpp b/src/test/fuzz/integer.cpp
--- a/src/test/fuzz/integer.cpp
+++ b/src/test/fuzz/integer.cpp
@@ -241,4 +241,43 @@
         (void)HasAllDesirableServiceFlags(service_flags);
         (void)MayHaveUsefulAddressDB(service_flags);
     }
+
+    {
+        CDataStream stream(SER_NETWORK, INIT_PROTO_VERSION);
+
+        ser_writedata64(stream, u64);
+        const uint64_t deserialized_u64 = ser_readdata64(stream);
+        assert(u64 == deserialized_u64 && stream.empty());
+
+        ser_writedata32(stream, u32);
+        const uint32_t deserialized_u32 = ser_readdata32(stream);
+        assert(u32 == deserialized_u32 && stream.empty());
+
+        ser_writedata32be(stream, u32);
+        const uint32_t deserialized_u32be = ser_readdata32be(stream);
+        assert(u32 == deserialized_u32be && stream.empty());
+
+        ser_writedata16(stream, u16);
+        const uint16_t deserialized_u16 = ser_readdata16(stream);
+        assert(u16 == deserialized_u16 && stream.empty());
+
+        ser_writedata16be(stream, u16);
+        const uint16_t deserialized_u16be = ser_readdata16be(stream);
+        assert(u16 == deserialized_u16be && stream.empty());
+
+        ser_writedata8(stream, u8);
+        const uint8_t deserialized_u8 = ser_readdata8(stream);
+        assert(u8 == deserialized_u8 && stream.empty());
+    }
+
+    {
+        CDataStream stream(SER_NETWORK, INIT_PROTO_VERSION);
+
+        WriteCompactSize(stream, u64);
+        try {
+            const uint64_t deserialized_u64 = ReadCompactSize(stream);
+            assert(u64 == deserialized_u64 && stream.empty());
+        } catch (const std::ios_base::failure &) {
+        }
+    }
 }
diff --git a/src/test/fuzz/util.h b/src/test/fuzz/util.h
--- a/src/test/fuzz/util.h
+++ b/src/test/fuzz/util.h
@@ -10,9 +10,11 @@
 #include <script/script.h>
 #include <serialize.h>
 #include <streams.h>
+#include <uint256.h>
+#include <version.h>
+
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
-#include <version.h>
 
 #include <cstdint>
 #include <string>
@@ -83,6 +85,16 @@
     return CScriptNum{fuzzed_data_provider.ConsumeIntegral<int64_t>()};
 }
 
+NODISCARD inline uint256
+ConsumeUInt256(FuzzedDataProvider &fuzzed_data_provider) noexcept {
+    const std::vector<uint8_t> v256 =
+        fuzzed_data_provider.ConsumeBytes<uint8_t>(sizeof(uint256));
+    if (v256.size() != sizeof(uint256)) {
+        return {};
+    }
+    return uint256{v256};
+}
+
 template <typename T> bool MultiplicationOverflow(T i, T j) {
     static_assert(std::is_integral<T>::value, "Integral required.");
     if (std::numeric_limits<T>::is_signed) {