diff --git a/cypress/integration/other/xss.spec.js b/cypress/integration/other/xss.spec.js
index 529eee16d..f605e98dc 100644
--- a/cypress/integration/other/xss.spec.js
+++ b/cypress/integration/other/xss.spec.js
@@ -110,4 +110,9 @@ describe('XSS', () => {
     cy.wait(1000);
     cy.get('#the-malware').should('not.exist');
   });
+  it('should sanitize cardinalities properly in class diagrams', () => {
+    cy.visit('http://localhost:9000/xss18.html');
+    cy.wait(1000);
+    cy.get('#the-malware').should('not.exist');
+  });
 });
diff --git a/cypress/platform/xss18.html b/cypress/platform/xss18.html
new file mode 100644
index 000000000..5dc7df621
--- /dev/null
+++ b/cypress/platform/xss18.html
@@ -0,0 +1,105 @@
+<html>
+  <head>
+    <link
+      href="https://fonts.googleapis.com/css?family=Montserrat&display=swap"
+      rel="stylesheet"
+    />
+    <link href="https://unpkg.com/tailwindcss@^1.0/dist/tailwind.min.css" rel="stylesheet">
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
+    <link href="https://fonts.googleapis.com/css?family=Noto+Sans+SC&display=swap" rel="stylesheet">
+    <style>
+      body {
+        /* background: rgb(221, 208, 208); */
+        /* background:#333; */
+        font-family: 'Arial';
+        /* font-size: 18px !important; */
+        }
+      h1 { color: grey;}
+      .mermaid2 {
+        display: none;
+      }
+      .mermaid svg {
+        /* font-size: 18px !important; */
+      }
+      .malware {
+        position: fixed;
+        bottom:0;
+        left:0;
+        right:0;
+        height: 150px;
+        background: red;
+        color: black;
+        display: flex;
+        display: flex;
+        justify-content: center;
+        align-items: center;
+        font-family: monospace;
+        font-size: 72px;
+      }
+    </style>
+  </head>
+  <body>
+    <div>Security check</div>
+    <div class="flex">
+      <div id="diagram" class="mermaid"></div>
+      <div id="res" class=""></div>
+  <script src="./mermaid.js"></script>
+    <script>
+      mermaid.parseError = function (err, hash) {
+        // console.error('Mermaid error: ', err);
+      };
+      mermaid.initialize({
+        theme: 'forest',
+        arrowMarkerAbsolute: true,
+        // themeCSS: '.edgePath .path {stroke: red;} .arrowheadPath {fill: red;}',
+        logLevel: 0,
+        state: {
+          defaultRenderer: 'dagre-d3',
+        },
+        flowchart: {
+          // defaultRenderer: 'dagre-wrapper',
+          nodeSpacing: 10,
+    curve: 'cardinal',
+    htmlLabels: true,
+        },
+        htmlLabels: true,
+        // gantt: { axisFormat: '%m/%d/%Y' },
+        sequence: { actorFontFamily: 'courier', actorMargin: 50, showSequenceNumbers: false },
+        // sequenceDiagram: { actorMargin: 300 } // deprecated
+        // fontFamily: '"times", sans-serif',
+        // fontFamily: 'courier',
+        fontSize: 18,
+        curve: 'basis',
+        // securityLevel: 'loose',
+        startOnLoad: false,
+        secure: ['secure', 'securityLevel', 'startOnLoad', 'maxTextSize'],
+        // themeVariables: {relationLabelColor: 'red'}
+      });
+      function callback() {
+  alert('It worked');
+}
+      function xssAttack() {
+        const div = document.createElement('div');
+        div.id = 'the-malware';
+        div.className = 'malware';
+        div.innerHTML = 'XSS Succeeded';
+        document.getElementsByTagName('body')[0].appendChild(div);
+        throw new Error('XSS Succeded');
+      }
+
+      var diagram = `classDiagram
+      Class "<img/src='x'/onerror=xssAttack(1)>" <--> "<img/src='x'/onerror=xssAttack(2)>" C2: Cool label`;
+
+// //   var diagram = "stateDiagram-v2\n";
+// //  diagram += "<img/src='1'/onerror"
+// diagram += '//via.placeholder.com/64\' width=64 />"]';
+// console.log(diagram);
+// document.querySelector('#diagram').innerHTML = diagram;
+mermaid.render('diagram', diagram, (res) => {
+  console.log(res);
+  document.querySelector('#res').innerHTML = res;
+});
+    </script>
+  </body>
+</html>
+
diff --git a/src/diagrams/class/classDb.js b/src/diagrams/class/classDb.js
index 34d839dab..ba33b5f77 100644
--- a/src/diagrams/class/classDb.js
+++ b/src/diagrams/class/classDb.js
@@ -96,6 +96,16 @@ export const addRelation = function (relation) {
   relation.id1 = splitClassNameAndType(relation.id1).className;
   relation.id2 = splitClassNameAndType(relation.id2).className;
 
+  relation.relationTitle1 = common.sanitizeText(
+    relation.relationTitle1.trim(),
+    configApi.getConfig()
+  );
+
+  relation.relationTitle2 = common.sanitizeText(
+    relation.relationTitle2.trim(),
+    configApi.getConfig()
+  );
+
   relations.push(relation);
 };
 
