diff --git a/dspace-server-webapp/src/main/java/org/dspace/app/rest/BitstreamRestController.java b/dspace-server-webapp/src/main/java/org/dspace/app/rest/BitstreamRestController.java
index 0c4bf35f45f..bf25b76aa5e 100644
--- a/dspace-server-webapp/src/main/java/org/dspace/app/rest/BitstreamRestController.java
+++ b/dspace-server-webapp/src/main/java/org/dspace/app/rest/BitstreamRestController.java
@@ -16,6 +16,7 @@
 import java.net.URI;
 import java.sql.SQLException;
 import java.util.List;
+import java.util.Locale;
 import java.util.UUID;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -133,7 +134,7 @@ public ResponseEntity retrieve(@PathVariable UUID uuid, HttpServletResponse resp
 
         Long lastModified = bitstreamService.getLastModified(bit);
         BitstreamFormat format = bit.getFormat(context);
-        String mimetype = format.getMIMEType();
+        String mimetype = StringUtils.defaultIfBlank(format.getMIMEType(), "application/octet-stream");
         String name = getBitstreamName(bit, format);
 
         if (StringUtils.isBlank(request.getHeader("Range"))) {
@@ -293,7 +294,8 @@ private boolean isNotAnErrorResponse(HttpServletResponse response) {
      */
     private boolean checkFormatForContentDisposition(BitstreamFormat format) {
         // Undefined or Unknown formats should ALWAYS be downloaded for additional security.
-        if (format == null || format.getSupportLevel() == BitstreamFormat.UNKNOWN) {
+        if (format == null || format.getSupportLevel() == BitstreamFormat.UNKNOWN
+            || StringUtils.isBlank(format.getMIMEType())) {
             return true;
         }
 
@@ -306,16 +308,24 @@ private boolean checkFormatForContentDisposition(BitstreamFormat format) {
             return true;
         }
 
-        // Define a download list of formats which DSpace forces to ALWAYS be downloaded.
-        // These formats can embed JavaScript which may be run in the user's browser if the file is opened inline.
-        // Therefore, DSpace blocks opening these formats inline as it could be used for an XSS attack.
-        List<String> downloadOnlyFormats = List.of("text/html", "text/javascript", "text/xml", "rdf");
+        // Compare MIME types without parameters or case differences.
+        String mimeType = StringUtils.substringBefore(format.getMIMEType(), ";").trim().toLowerCase(Locale.ROOT);
+        if (mimeType.isEmpty() || mimeType.endsWith("+xml") || mimeType.startsWith("text/javascript")) {
+            return true;
+        }
+
+        // Active formats must download regardless of configuration.
+        List<String> downloadOnlyFormats = List.of("text/html", "text/javascript", "text/xml", "application/xml",
+            "rdf", "application/javascript", "application/ecmascript", "text/ecmascript",
+            "application/x-javascript", "application/x-ecmascript", "text/x-javascript", "text/x-ecmascript",
+            "text/jscript", "text/livescript");
 
         // Combine our two lists
         List<String> formats = ListUtils.union(downloadOnlyFormats, configuredFormats);
 
         // See if the passed in format's MIME type or file extension is listed.
-        boolean download = formats.contains(format.getMIMEType());
+        boolean download = formats.stream().anyMatch(value ->
+            mimeType.equalsIgnoreCase(StringUtils.substringBefore(value, ";").trim()));
         if (!download) {
             for (String ext : format.getExtensions()) {
                 if (formats.contains(ext)) {
diff --git a/dspace-server-webapp/src/test/java/org/dspace/app/rest/BitstreamRestControllerIT.java b/dspace-server-webapp/src/test/java/org/dspace/app/rest/BitstreamRestControllerIT.java
index 7e07c707216..6b0086a72ad 100644
--- a/dspace-server-webapp/src/test/java/org/dspace/app/rest/BitstreamRestControllerIT.java
+++ b/dspace-server-webapp/src/test/java/org/dspace/app/rest/BitstreamRestControllerIT.java
@@ -1432,6 +1432,68 @@ public void checkWildcardContentDispositionFormats() throws Exception {
     }
 
 
+    @Test
+    public void checkActiveContentFormatsNeverServedInline() throws Exception {
+        String[] mimeTypes = {
+            "image/svg+xml", "application/xhtml+xml", "image/SVG+XML", "APPLICATION/XHTML+XML",
+            "text/html; charset=utf-8", "application/javascript", "application/ecmascript",
+            "text/ecmascript", "application/x-javascript", "application/x-ecmascript",
+            "text/x-javascript", "text/x-ecmascript", "text/jscript", "text/livescript", "text/javascript1.5"
+        };
+        configurationService.setProperty("webui.content_disposition_format", new String[0]);
+
+        context.turnOffAuthorisationSystem();
+        Community community = CommunityBuilder.createCommunity(context).build();
+        Collection collection = CollectionBuilder.createCollection(context, community).build();
+        Item item = ItemBuilder.createItem(context, collection).build();
+        context.restoreAuthSystemState();
+
+        for (String mimeType : mimeTypes) {
+            context.turnOffAuthorisationSystem();
+            // Exercise registered active formats, not the unknown-format fallback.
+            createBitstreamFormat(context).withMimeType(mimeType)
+                .withShortDescription("Active " + mimeType).withSupportLevel(KNOWN).build();
+            item = context.reloadEntity(item);
+            Bitstream file = BitstreamBuilder.createBitstream(context, item, toInputStream("test", UTF_8))
+                .withMimeType(mimeType).build();
+            context.restoreAuthSystemState();
+
+            String contentType = mimeType.split(";")[0] + ";charset=UTF-8";
+            configurationService.setProperty("webui.content_disposition_threshold", 8388608);
+            verifyBitstreamDownload(file, contentType, true);
+            configurationService.setProperty("webui.content_disposition_threshold", -1);
+            verifyBitstreamDownload(file, contentType, true);
+        }
+    }
+
+    @Test
+    public void checkInlineDispositionSizeLimit() throws Exception {
+        context.turnOffAuthorisationSystem();
+        bitstream.setFormat(context, bitstreamFormatService.findByMIMEType(context, "application/pdf"));
+        bitstreamService.update(context, bitstream);
+        context.restoreAuthSystemState();
+
+        configurationService.setProperty("webui.content_disposition_threshold", bitstream.getSizeBytes());
+        verifyBitstreamDownload(bitstream, "application/pdf;charset=UTF-8", false);
+        configurationService.setProperty("webui.content_disposition_threshold", bitstream.getSizeBytes() - 1);
+        verifyBitstreamDownload(bitstream, "application/pdf;charset=UTF-8", true);
+        configurationService.setProperty("webui.content_disposition_threshold", -1);
+        verifyBitstreamDownload(bitstream, "application/pdf;charset=UTF-8", false);
+    }
+
+    @Test
+    public void checkMissingMimeTypeDownloads() throws Exception {
+        configurationService.setProperty("webui.content_disposition_format", new String[0]);
+        for (String mimeType : new String[] {null, "", " "}) {
+            context.turnOffAuthorisationSystem();
+            supportedFormat = context.reloadEntity(supportedFormat);
+            supportedFormat.setMIMEType(mimeType);
+            bitstreamFormatService.update(context, supportedFormat);
+            context.restoreAuthSystemState();
+            verifyBitstreamDownload(bitstream, "application/octet-stream;charset=UTF-8", true);
+        }
+    }
+
     private void verifyBitstreamDownload(Bitstream file, String contentType, boolean shouldDownload) throws Exception {
         String token = getAuthToken(admin.getEmail(), password);
         String header = getClient(token).perform(get("/api/core/bitstreams/" + file.getID() + "/content")