diff --git a/server/controllers/__tests__/courseCtrlHelpers.test.js b/server/controllers/__tests__/courseCtrlHelpers.test.js
index 44182c64..83bbc181 100644
--- a/server/controllers/__tests__/courseCtrlHelpers.test.js
+++ b/server/controllers/__tests__/courseCtrlHelpers.test.js
@@ -1,4 +1,8 @@
-import { calculateInitiallySelectedSemester, generateSelectedSemesterBasedOnDate } from '../courseCtrlHelpers'
+import {
+  calculateInitiallySelectedSemester,
+  generateSelectedSemesterBasedOnDate,
+  isValidCourseCode,
+} from '../courseCtrlHelpers'
 
 const activeSemesters = [
   {
@@ -149,4 +153,30 @@ describe('courseCtrlHelpers', () => {
       expect(generateSelectedSemesterBasedOnDate(new Date('2024-12-01'))).toBe(expectedSemester)
     })
   })
+
+  describe('isValidCourseCode', () => {
+    test.each([null, undefined])('returns false if given courseCode is %s', courseCode => {
+      expect(isValidCourseCode(courseCode)).toBe(false)
+    })
+    test.each(['', '1', '12', 123, '1234', 'asdfg'])(
+      'returns false if given courseCode is shorter than 6 characters: %s',
+      courseCode => {
+        expect(isValidCourseCode(courseCode)).toBe(false)
+      }
+    )
+
+    test.each(['12345678', 'SF1523423490234'])(
+      'returns false if given courseCode is longer than 7 characters: %s',
+      courseCode => {
+        expect(isValidCourseCode(courseCode)).toBe(false)
+      }
+    )
+
+    test.each(['123456', 123456, '1234567', 1234567])(
+      'returns true if given courseCode has length of 6 or 7 characters: %s',
+      courseCode => {
+        expect(isValidCourseCode(courseCode)).toBe(true)
+      }
+    )
+  })
 })
diff --git a/server/controllers/courseCtrl.js b/server/controllers/courseCtrl.js
index a33275ca..b5995de0 100644
--- a/server/controllers/courseCtrl.js
+++ b/server/controllers/courseCtrl.js
@@ -14,11 +14,13 @@ const { getServerSideFunctions } = require('../utils/serverSideRendering')
 const { INFORM_IF_IMPORTANT_INFO_IS_MISSING } = require('../util/constants')
 const { getFilteredData: getFilteredData } = require('../apiCalls/filteredData')
 const { createCourseWebContext } = require('../util/webContextUtil')
-const { calculateInitiallySelectedSemester } = require('./courseCtrlHelpers')
+const { HttpError } = require('../HttpError')
+const { calculateInitiallySelectedSemester, isValidCourseCode } = require('./courseCtrlHelpers')
 
 const extractUpperCaseCourseCodeOrThrow = req => {
   const { courseCode } = req.params
-  if (!courseCode) throw new Error('Missing parameter courseCode')
+  if (!courseCode) throw new HttpError(400, 'Missing parameter courseCode')
+  if (!isValidCourseCode(courseCode)) throw new HttpError(400, `Invalid course code: ${courseCode}`)
   return courseCode.toUpperCase()
 }
 
@@ -82,14 +84,14 @@ const getLanguageOrDefault = res => languageUtils.getLanguage(res) || 'sv'
 /*                    COURSE PAGE SETTINGS AND RENDERING                          */
 /* ****************************************************************************** */
 async function getIndex(req, res, next) {
-  const courseCode = extractUpperCaseCourseCodeOrThrow(req)
-  const language = getLanguageOrDefault(res)
+  try {
+    const courseCode = extractUpperCaseCourseCodeOrThrow(req)
+    const language = getLanguageOrDefault(res)
 
-  const klaroAnalyticsConsentCookie = extractKlaroAnalyticsCookie(req)
+    const klaroAnalyticsConsentCookie = extractKlaroAnalyticsCookie(req)
 
-  const { getCompressedData, renderStaticPage } = getServerSideFunctions()
+    const { getCompressedData, renderStaticPage } = getServerSideFunctions()
 
-  try {
     const startSemesterFromQuery = extractStartSemesterFromQuery(req)
 
     const memoList = await getMemoList(courseCode)
@@ -142,7 +144,7 @@ async function getIndex(req, res, next) {
       breadcrumbsList,
     })
   } catch (err) {
-    const errorCodesThatShouldNotBeLogged = [403, 404]
+    const errorCodesThatShouldNotBeLogged = [400, 403, 404]
     let statusCode
     if (err.response) {
       statusCode = err.response.status
diff --git a/server/controllers/courseCtrlHelpers.js b/server/controllers/courseCtrlHelpers.js
index be88339b..e56a2e31 100644
--- a/server/controllers/courseCtrlHelpers.js
+++ b/server/controllers/courseCtrlHelpers.js
@@ -54,8 +54,19 @@ const parseOrSetEmpty = (value, language, setEmpty = false) => {
   return value ? value : emptyText
 }
 
+const VALID_COURSE_CODE_LENGTHS = [6, 7]
+
+/**
+ *
+ *
+ * @param {string} courseCode
+ * @returns true if the given courseCode has a length of 6 or 7 characters
+ */
+const isValidCourseCode = courseCode => !!courseCode && VALID_COURSE_CODE_LENGTHS.includes(courseCode.toString().length)
+
 module.exports = {
   calculateInitiallySelectedSemester,
   generateSelectedSemesterBasedOnDate,
   parseOrSetEmpty,
+  isValidCourseCode,
 }