diff --git a/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java b/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
index 83fb7d248..c5c82f91b 100644
--- a/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
+++ b/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
@@ -1263,17 +1263,18 @@ private void consumeSettingsFrame(final ByteBuffer payload) throws IOException {
             final H2Param param = H2Param.valueOf(code);
             if (param != null) {
                 validateSetting(param, value);
+                final int boundedValue = value < 0 ? Integer.MAX_VALUE : value;
                 switch (param) {
                     case HEADER_TABLE_SIZE:
                         try {
-                            configBuilder.setHeaderTableSize(value);
+                            configBuilder.setHeaderTableSize(boundedValue);
                         } catch (final IllegalArgumentException ex) {
                             throw new H2ConnectionException(H2Error.PROTOCOL_ERROR, ex.getMessage());
                         }
                         break;
                     case MAX_CONCURRENT_STREAMS:
                         try {
-                            configBuilder.setMaxConcurrentStreams(value);
+                            configBuilder.setMaxConcurrentStreams(boundedValue);
                         } catch (final IllegalArgumentException ex) {
                             throw new H2ConnectionException(H2Error.PROTOCOL_ERROR, ex.getMessage());
                         }
@@ -1301,7 +1302,7 @@ private void consumeSettingsFrame(final ByteBuffer payload) throws IOException {
                         break;
                     case MAX_HEADER_LIST_SIZE:
                         try {
-                            configBuilder.setMaxHeaderListSize(value);
+                            configBuilder.setMaxHeaderListSize(boundedValue);
                         } catch (final IllegalArgumentException ex) {
                             throw new H2ConnectionException(H2Error.PROTOCOL_ERROR, ex.getMessage());
                         }
diff --git a/httpcore5-h2/src/test/java/org/apache/hc/core5/http2/impl/nio/TestAbstractH2StreamMultiplexer.java b/httpcore5-h2/src/test/java/org/apache/hc/core5/http2/impl/nio/TestAbstractH2StreamMultiplexer.java
index b5f50a96c..6d4f385ad 100644
--- a/httpcore5-h2/src/test/java/org/apache/hc/core5/http2/impl/nio/TestAbstractH2StreamMultiplexer.java
+++ b/httpcore5-h2/src/test/java/org/apache/hc/core5/http2/impl/nio/TestAbstractH2StreamMultiplexer.java
@@ -2393,6 +2393,91 @@ void testRemoteHeaderTableSizeChangesRemainLocallyBounded() throws Exception {
         }
     }
 
+
+    @Test
+    void testUnsignedHeaderTableSizeSettingAccepted() throws Exception {
+        final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
+                protocolIOSession,
+                FRAME_FACTORY,
+                StreamIdGenerator.ODD,
+                httpProcessor,
+                CharCodingConfig.DEFAULT,
+                H2Config.custom().build(),
+                h2StreamListener,
+                () -> streamHandler);
+        try {
+            final ByteBuffer payload = ByteBuffer.allocate(6);
+            payload.putShort((short) H2Param.HEADER_TABLE_SIZE.getCode());
+            payload.putInt(-1); // 0xffffffff
+            payload.flip();
+
+            final RawFrame settingsFrame =
+                    new RawFrame(FrameType.SETTINGS.getValue(), 0, 0, payload);
+
+            Assertions.assertDoesNotThrow(
+                    () -> mux.onInput(ByteBuffer.wrap(encodeFrame(settingsFrame))));
+            Assertions.assertEquals(
+                    H2Config.INIT.getHeaderTableSize(),
+                    getHPackEncoder(mux).getMaxTableSize());
+        } finally {
+            mux.close();
+        }
+    }
+
+    @Test
+    void testUnsignedMaxConcurrentStreamsSettingAccepted() throws Exception {
+        final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
+                protocolIOSession,
+                FRAME_FACTORY,
+                StreamIdGenerator.ODD,
+                httpProcessor,
+                CharCodingConfig.DEFAULT,
+                H2Config.custom().build(),
+                h2StreamListener,
+                () -> streamHandler);
+        try {
+            final ByteBuffer payload = ByteBuffer.allocate(6);
+            payload.putShort((short) H2Param.MAX_CONCURRENT_STREAMS.getCode());
+            payload.putInt(Integer.MIN_VALUE); // 0x80000000
+            payload.flip();
+
+            final RawFrame settingsFrame =
+                    new RawFrame(FrameType.SETTINGS.getValue(), 0, 0, payload);
+
+            Assertions.assertDoesNotThrow(
+                    () -> mux.onInput(ByteBuffer.wrap(encodeFrame(settingsFrame))));
+        } finally {
+            mux.close();
+        }
+    }
+
+    @Test
+    void testUnsignedMaxHeaderListSizeSettingAccepted() throws Exception {
+        final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
+                protocolIOSession,
+                FRAME_FACTORY,
+                StreamIdGenerator.ODD,
+                httpProcessor,
+                CharCodingConfig.DEFAULT,
+                H2Config.custom().build(),
+                h2StreamListener,
+                () -> streamHandler);
+        try {
+            final ByteBuffer payload = ByteBuffer.allocate(6);
+            payload.putShort((short) H2Param.MAX_HEADER_LIST_SIZE.getCode());
+            payload.putInt(-1); // 0xffffffff
+            payload.flip();
+
+            final RawFrame settingsFrame =
+                    new RawFrame(FrameType.SETTINGS.getValue(), 0, 0, payload);
+
+            Assertions.assertDoesNotThrow(
+                    () -> mux.onInput(ByteBuffer.wrap(encodeFrame(settingsFrame))));
+        } finally {
+            mux.close();
+        }
+    }
+
     private static HPackEncoder getHPackEncoder(final AbstractH2StreamMultiplexer multiplexer) throws Exception {
         final Field field = AbstractH2StreamMultiplexer.class.getDeclaredField("hPackEncoder");
         field.setAccessible(true);