diff --git a/csaf_2_1/mandatoryTests.js b/csaf_2_1/mandatoryTests.js
index 5a5a8a7b..f6ce9042 100644
--- a/csaf_2_1/mandatoryTests.js
+++ b/csaf_2_1/mandatoryTests.js
@@ -19,7 +19,6 @@ export {
   mandatoryTest_6_1_27_1,
   mandatoryTest_6_1_27_2,
   mandatoryTest_6_1_27_3,
-  mandatoryTest_6_1_27_4,
   mandatoryTest_6_1_27_6,
   mandatoryTest_6_1_27_7,
   mandatoryTest_6_1_27_8,
@@ -42,6 +41,7 @@ export { mandatoryTest_6_1_9 } from './mandatoryTests/mandatoryTest_6_1_9.js'
 export { mandatoryTest_6_1_10 } from './mandatoryTests/mandatoryTest_6_1_10.js'
 export { mandatoryTest_6_1_11 } from './mandatoryTests/mandatoryTest_6_1_11.js'
 export { mandatoryTest_6_1_13 } from './mandatoryTests/mandatoryTest_6_1_13.js'
+export { mandatoryTest_6_1_27_4 } from './mandatoryTests/mandatoryTest_6_1_27_4.js'
 export { mandatoryTest_6_1_27_5 } from './mandatoryTests/mandatoryTest_6_1_27_5.js'
 export { mandatoryTest_6_1_27_12 } from './mandatoryTests/mandatoryTest_6_1_27_12.js'
 export { mandatoryTest_6_1_27_14 } from './mandatoryTests/mandatoryTest_6_1_27_14.js'
diff --git a/csaf_2_1/mandatoryTests/mandatoryTest_6_1_27_4.js b/csaf_2_1/mandatoryTests/mandatoryTest_6_1_27_4.js
new file mode 100644
index 00000000..07ede3e3
--- /dev/null
+++ b/csaf_2_1/mandatoryTests/mandatoryTest_6_1_27_4.js
@@ -0,0 +1,61 @@
+import { Ajv } from 'ajv/dist/jtd.js'
+
+const ajv = new Ajv()
+
+/*
+  This is the jtd schema that needs to match the input document so that the
+  test is activated. If this schema doesn't match it normally means that the input
+  document does not validate against the csaf json schema or optional fields that
+  the test checks are not present.
+ */
+const inputSchema = /** @type {const} */ ({
+  additionalProperties: true,
+  properties: {
+    document: {
+      additionalProperties: true,
+      properties: {
+        category: {
+          type: 'string',
+        },
+      },
+    },
+    product_tree: {},
+  },
+})
+
+const validate = ajv.compile(inputSchema)
+
+/**
+ * It MUST be tested that the element /product_tree exists.
+ *
+ * The relevant values for /document/category are:
+ *
+ * @param {any} doc
+ */
+export function mandatoryTest_6_1_27_4(doc) {
+  /** @type {Array<{ message: string; instancePath: string }>} */
+  const errors = []
+  let isValid = true
+
+  if (!validate(doc)) {
+    return { errors, isValid }
+  }
+
+  const checkedDocumentCategories = new Set([
+    'csaf_security_advisory',
+    'csaf_vex',
+    'csaf_deprecated_security_advisory',
+  ])
+
+  if (
+    doc.product_tree === undefined &&
+    checkedDocumentCategories.has(doc.document?.category)
+  ) {
+    isValid = false
+    errors.push({
+      instancePath: '/product_tree',
+      message: 'needs a product_tree',
+    })
+  }
+  return { errors, isValid }
+}
diff --git a/tests/csaf_2_1/mandatoryTest_6_1_27_4.js b/tests/csaf_2_1/mandatoryTest_6_1_27_4.js
new file mode 100644
index 00000000..ec6a8398
--- /dev/null
+++ b/tests/csaf_2_1/mandatoryTest_6_1_27_4.js
@@ -0,0 +1,28 @@
+import assert from 'node:assert/strict'
+import { mandatoryTest_6_1_27_4 } from '../../csaf_2_1/mandatoryTests/mandatoryTest_6_1_27_4.js'
+
+describe('mandatoryTest_6_1_27_4', function () {
+  it('only runs on relevant documents', function () {
+    assert.equal(mandatoryTest_6_1_27_4({ document: 'mydoc' }).isValid, true)
+  })
+
+  it('returns invalid for documents without product_tree with relevant category', function () {
+    assert.equal(
+      mandatoryTest_6_1_27_4({
+        document: { category: 'csaf_deprecated_security_advisory' },
+        vulnerabilities: [{}],
+      }).isValid,
+      false
+    )
+  })
+
+  it('returns valid for documents with product_tree with relevant category', function () {
+    assert.equal(
+      mandatoryTest_6_1_27_4({
+        document: { category: 'csaf_deprecated_security_advisory' },
+        product_tree: [{}],
+      }).isValid,
+      true
+    )
+  })
+})
diff --git a/tests/csaf_2_1/oasis.js b/tests/csaf_2_1/oasis.js
index d13519a2..7a8f03f0 100644
--- a/tests/csaf_2_1/oasis.js
+++ b/tests/csaf_2_1/oasis.js
@@ -12,7 +12,6 @@ import * as mandatory from '../../csaf_2_1/mandatoryTests.js'
 const excluded = [
   '6.1.26',
   '6.1.27.3',
-  '6.1.27.4',
   '6.1.27.6',
   '6.1.27.11',
   '6.1.27.13',