diff --git a/doc/sphinx-guides/source/installation/config.rst b/doc/sphinx-guides/source/installation/config.rst
index e9ad3bdfe24..ddb15e45fbe 100644
--- a/doc/sphinx-guides/source/installation/config.rst
+++ b/doc/sphinx-guides/source/installation/config.rst
@@ -3951,8 +3951,10 @@ Linked Data Notifications (LDN) Allowed Hosts
 +++++++++++++++++++++++++++++++++++++++++++++
 
 Dataverse supports receiving LDN notifications via the /api/inbox endpoint. The dataverse.ldn.allowed-hosts allows you to specify the list of host IP addresses from which LDN notifications can be received, or ``*`` to receive messages from anywhere.
+Note that since the Inbox endpoint does not require authentication, allowing un-trusted hosts via ``*`` is not recommended for production.
 
 Example: ``dataverse.ldn.allowed-hosts=*``
+Example: ``dataverse.ldn.allowed-hosts=172.16.234.56,172.16.234.57``
 
 COAR Notify Relationship Announcement Notify Superusers Only
 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
diff --git a/src/main/java/edu/harvard/iq/dataverse/api/ldn/COARNotifyRelationshipAnnouncement.java b/src/main/java/edu/harvard/iq/dataverse/api/ldn/COARNotifyRelationshipAnnouncement.java
index 84f5702cf40..cfeb034782b 100644
--- a/src/main/java/edu/harvard/iq/dataverse/api/ldn/COARNotifyRelationshipAnnouncement.java
+++ b/src/main/java/edu/harvard/iq/dataverse/api/ldn/COARNotifyRelationshipAnnouncement.java
@@ -9,8 +9,9 @@
 import edu.harvard.iq.dataverse.UserNotificationServiceBean;
 import edu.harvard.iq.dataverse.authorization.Permission;
 import edu.harvard.iq.dataverse.pidproviders.PidProvider;
+import edu.harvard.iq.dataverse.pidproviders.doi.AbstractDOIProvider;
+import edu.harvard.iq.dataverse.pidproviders.doi.UnmanagedDOIProvider;
 import edu.harvard.iq.dataverse.settings.JvmSettings;
-import edu.harvard.iq.dataverse.util.json.JsonLDNamespace;
 import edu.harvard.iq.dataverse.util.json.JsonLDTerm;
 import edu.harvard.iq.dataverse.util.json.JsonUtil;
 
@@ -70,7 +71,6 @@ public COARNotifyRelationshipAnnouncement(
      * Process a COAR Notify Relationship Announcement message.
      *
      * @param msgObject The JSON-LD message object
-     * @return true if the message was successfully processed, false otherwise
      */
     public void processMessage(JsonObject msgObject) {
         // Extract subject, object, and relationship from the message
@@ -168,7 +168,11 @@ private ResourceMetadata retrieveResourceMetadata(String subjectId) {
 
                     // Step 3: Retrieve and parse DataCite XML
                     if (dataciteXmlUrl != null) {
-                        parseDataCiteXml(dataciteXmlUrl, client, metadata);
+                        if (isTrustedDataCiteUrl(dataciteXmlUrl)) {
+                            parseDataCiteXml(dataciteXmlUrl, client, metadata);
+                        } else {
+                            logger.warning("DataCite XML URL is not from a trusted source: " + dataciteXmlUrl);
+                        }
                     } else {
                         logger.fine("No DataCite XML URL found in Signposting links");
                     }
@@ -189,10 +193,6 @@ private ResourceMetadata retrieveResourceMetadata(String subjectId) {
         return metadata;
     }
 
-    /**
-     * Extract DataCite XML URL from Signposting Link headers.
-     */
-
 /**
  * Extract DataCite XML URL from Signposting Link headers.
  */
@@ -232,6 +232,33 @@ private String extractDataCiteXmlUrl(CloseableHttpResponse headResponse) {
     return null;
 }
 
+    /**
+     * Validate that the URL is a trusted source for DataCite XML.
+     * Supports standard DOI resolvers and DataCite API.
+     */
+    boolean isTrustedDataCiteUrl(String url) {
+        if (url == null || url.isBlank()) {
+            return false;
+        }
+        url = url.toLowerCase();
+
+        String doiPart = null;
+        if (url.startsWith(AbstractDOIProvider.DOI_RESOLVER_URL)) {
+            doiPart = url.substring(AbstractDOIProvider.DOI_RESOLVER_URL.length());
+        } else if (url.startsWith(AbstractDOIProvider.HTTP_DOI_RESOLVER_URL)) {
+            doiPart = url.substring(AbstractDOIProvider.HTTP_DOI_RESOLVER_URL.length());
+        } else if (url.startsWith(AbstractDOIProvider.DXDOI_RESOLVER_URL)) {
+            doiPart = url.substring(AbstractDOIProvider.DXDOI_RESOLVER_URL.length());
+        } else if (url.startsWith(AbstractDOIProvider.HTTP_DXDOI_RESOLVER_URL)) {
+            doiPart = url.substring(AbstractDOIProvider.HTTP_DXDOI_RESOLVER_URL.length());
+        }
+
+        if (doiPart != null) {
+            return (new UnmanagedDOIProvider()).parsePersistentId(AbstractDOIProvider.DOI_PROTOCOL, doiPart) != null;
+        }
+        return false;
+    }
+
     /**
      * Parse DataCite XML to extract title and resource type.
      */
diff --git a/src/test/java/edu/harvard/iq/dataverse/api/ldn/COARNotifyRelationshipAnnouncementTest.java b/src/test/java/edu/harvard/iq/dataverse/api/ldn/COARNotifyRelationshipAnnouncementTest.java
new file mode 100644
index 00000000000..c0f2de888e8
--- /dev/null
+++ b/src/test/java/edu/harvard/iq/dataverse/api/ldn/COARNotifyRelationshipAnnouncementTest.java
@@ -0,0 +1,46 @@
+package edu.harvard.iq.dataverse.api.ldn;
+
+import edu.harvard.iq.dataverse.DatasetServiceBean;
+import edu.harvard.iq.dataverse.DataverseRoleServiceBean;
+import edu.harvard.iq.dataverse.RoleAssigneeServiceBean;
+import edu.harvard.iq.dataverse.UserNotificationServiceBean;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class COARNotifyRelationshipAnnouncementTest {
+
+    private COARNotifyRelationshipAnnouncement handler;
+
+    @BeforeEach
+    public void setUp() {
+        DatasetServiceBean datasetService = Mockito.mock(DatasetServiceBean.class);
+        UserNotificationServiceBean userNotificationService = Mockito.mock(UserNotificationServiceBean.class);
+        DataverseRoleServiceBean roleService = Mockito.mock(DataverseRoleServiceBean.class);
+        RoleAssigneeServiceBean roleAssigneeService = Mockito.mock(RoleAssigneeServiceBean.class);
+        handler = new COARNotifyRelationshipAnnouncement(datasetService, userNotificationService, roleService, roleAssigneeService);
+    }
+
+    @Test
+    public void testIsTrustedDataCiteUrl() {
+        // Trusted DOI resolvers
+        assertTrue(handler.isTrustedDataCiteUrl("https://doi.org/10.7910/DVN/TJCLKP"));
+        assertTrue(handler.isTrustedDataCiteUrl("http://doi.org/10.7910/DVN/TJCLKP"));
+        assertTrue(handler.isTrustedDataCiteUrl("https://dx.doi.org/10.7910/DVN/TJCLKP"));
+        assertTrue(handler.isTrustedDataCiteUrl("http://dx.doi.org/10.7910/DVN/TJCLKP"));
+
+        // Invalid DOI
+        assertFalse(handler.isTrustedDataCiteUrl("https://doi.org/not-a-doi"));
+
+
+        // Untrusted sources
+        assertFalse(handler.isTrustedDataCiteUrl("https://example.com/metadata.xml"));
+        assertFalse(handler.isTrustedDataCiteUrl("https://malicious.org/doi.org/10.1234/5678"));
+        
+        // Null and empty
+        assertFalse(handler.isTrustedDataCiteUrl(null));
+        assertFalse(handler.isTrustedDataCiteUrl(""));
+    }
+}