diff --git a/Dockerfile b/Dockerfile
index 41a05a1f4..8e0598c4b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -30,8 +30,8 @@ ARG TOMCAT_JRE=jdk8
 # Use official maven image for the build
 FROM maven:3-jdk-8 AS builder
 
-# Install chromium browser for sake of JavaScript unit tests
-RUN apt-get update && apt-get install -y chromium
+# Install firefox browser for sake of JavaScript unit tests
+RUN apt-get update && apt-get install -y firefox-esr
 
 # Use args to build radius auth extension such as
 # `--build-arg BUILD_PROFILE=lgpl-extensions`
diff --git a/guacamole-common-js/.gitignore b/guacamole-common-js/.gitignore
index 9bbff7b8c..876bf8396 100644
--- a/guacamole-common-js/.gitignore
+++ b/guacamole-common-js/.gitignore
@@ -1,4 +1,5 @@
-node/*
-node_modules/*
+node/
+node_modules/
 target/
+.tmp/
 *~
diff --git a/guacamole-common-js/karma-ci.conf.js b/guacamole-common-js/karma-ci.conf.js
index 13815ecb0..859335ba1 100644
--- a/guacamole-common-js/karma-ci.conf.js
+++ b/guacamole-common-js/karma-ci.conf.js
@@ -17,6 +17,10 @@
  * under the License.
  */
 
+/**
+ * A karma configuration intended for use in builds or CI. Runs all discovered
+ * unit tests under a headless firefox browser and immediately exits.
+ */
 module.exports = function(config) {
   config.set({
 
@@ -34,17 +38,17 @@ module.exports = function(config) {
     // Disable automatic test running on changed files
     autoWatch: false,
 
-    // Use a headless chromium browser to run the tests
-    // --no-sandbox required when running in docker build - for more, see
-    // https://github.com/karma-runner/karma-chrome-launcher/issues/158
-    // TODON'T: THIS
-    browsers: ['ChromiumHeadlessNoSandbox'],
+    // Use a headless firefox browser to run the tests
+    browsers: ['FirefoxHeadless'],
     customLaunchers: {
-      ChromiumHeadlessNoSandbox: {
-        base: 'ChromiumHeadless',
-        flags: ['--no-sandbox']
+      'FirefoxHeadless': {
+        base: 'Firefox',
+        flags: [
+            '--headless'
+        ]
       }
     }
 
-  })
-}
+  });
+  
+};
diff --git a/guacamole-common-js/package-lock.json b/guacamole-common-js/package-lock.json
index a370f49bd..5c08e1727 100644
--- a/guacamole-common-js/package-lock.json
+++ b/guacamole-common-js/package-lock.json
@@ -6,7 +6,7 @@
     "": {
       "devDependencies": {
         "karma": "^6.4.1",
-        "karma-chrome-launcher": "^3.1.1",
+        "karma-firefox-launcher": "^2.1.2",
         "karma-jasmine": "^5.1.0"
       }
     },
@@ -552,20 +552,6 @@
       "integrity": "sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==",
       "dev": true
     },
-    "node_modules/fsevents": {
-      "version": "2.3.2",
-      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
-      "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
-      "dev": true,
-      "hasInstallScript": true,
-      "optional": true,
-      "os": [
-        "darwin"
-      ],
-      "engines": {
-        "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
-      }
-    },
     "node_modules/function-bind": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.1.tgz",
@@ -736,6 +722,21 @@
         "node": ">=8"
       }
     },
+    "node_modules/is-docker": {
+      "version": "2.2.1",
+      "resolved": "https://registry.npmjs.org/is-docker/-/is-docker-2.2.1.tgz",
+      "integrity": "sha512-F+i2BKsFrH66iaUFc0woD8sLy8getkwTwtOBjvs56Cx4CgJDeKQeqfz8wAYiSb8JOprWhHH5p77PbmYCvvUuXQ==",
+      "dev": true,
+      "bin": {
+        "is-docker": "cli.js"
+      },
+      "engines": {
+        "node": ">=8"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
     "node_modules/is-extglob": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/is-extglob/-/is-extglob-2.1.1.tgz",
@@ -775,6 +776,18 @@
         "node": ">=0.12.0"
       }
     },
+    "node_modules/is-wsl": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/is-wsl/-/is-wsl-2.2.0.tgz",
+      "integrity": "sha512-fKzAra0rGJUUBwGBgNkHZuToZcn+TtXHpeCgmkMJMMYx1sQDYaCSyjJBSCa2nH1DGm7s3n1oBnohoVTBaN7Lww==",
+      "dev": true,
+      "dependencies": {
+        "is-docker": "^2.0.0"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/isbinaryfile": {
       "version": "4.0.10",
       "resolved": "https://registry.npmjs.org/isbinaryfile/-/isbinaryfile-4.0.10.tgz",
@@ -846,13 +859,14 @@
         "node": ">= 10"
       }
     },
-    "node_modules/karma-chrome-launcher": {
-      "version": "3.1.1",
-      "resolved": "https://registry.npmjs.org/karma-chrome-launcher/-/karma-chrome-launcher-3.1.1.tgz",
-      "integrity": "sha512-hsIglcq1vtboGPAN+DGCISCFOxW+ZVnIqhDQcCMqqCp+4dmJ0Qpq5QAjkbA0X2L9Mi6OBkHi2Srrbmm7pUKkzQ==",
+    "node_modules/karma-firefox-launcher": {
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/karma-firefox-launcher/-/karma-firefox-launcher-2.1.2.tgz",
+      "integrity": "sha512-VV9xDQU1QIboTrjtGVD4NCfzIH7n01ZXqy/qpBhnOeGVOkG5JYPEm8kuSd7psHE6WouZaQ9Ool92g8LFweSNMA==",
       "dev": true,
       "dependencies": {
-        "which": "^1.2.1"
+        "is-wsl": "^2.2.0",
+        "which": "^2.0.1"
       }
     },
     "node_modules/karma-jasmine": {
@@ -1482,15 +1496,18 @@
       }
     },
     "node_modules/which": {
-      "version": "1.3.1",
-      "resolved": "https://registry.npmjs.org/which/-/which-1.3.1.tgz",
-      "integrity": "sha512-HxJdYWq1MTIQbJ3nw0cqssHoTNU267KlrDuGZ1WYlxDStUtKUhOaJmh112/TZmHxxUfuJqPXSOm7tDyas0OSIQ==",
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
+      "integrity": "sha512-BLI3Tl1TW3Pvl70l3yq3Y64i+awpwXqsGBYWkkqMtnbXgrMD+yj7rhW0kuEDxzJaYXGjEW5ogapKNMEKNMjibA==",
       "dev": true,
       "dependencies": {
         "isexe": "^2.0.0"
       },
       "bin": {
-        "which": "bin/which"
+        "node-which": "bin/node-which"
+      },
+      "engines": {
+        "node": ">= 8"
       }
     },
     "node_modules/wrap-ansi": {
@@ -2002,13 +2019,6 @@
       "integrity": "sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==",
       "dev": true
     },
-    "fsevents": {
-      "version": "2.3.2",
-      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
-      "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
-      "dev": true,
-      "optional": true
-    },
     "function-bind": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.1.tgz",
@@ -2142,6 +2152,12 @@
         "binary-extensions": "^2.0.0"
       }
     },
+    "is-docker": {
+      "version": "2.2.1",
+      "resolved": "https://registry.npmjs.org/is-docker/-/is-docker-2.2.1.tgz",
+      "integrity": "sha512-F+i2BKsFrH66iaUFc0woD8sLy8getkwTwtOBjvs56Cx4CgJDeKQeqfz8wAYiSb8JOprWhHH5p77PbmYCvvUuXQ==",
+      "dev": true
+    },
     "is-extglob": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/is-extglob/-/is-extglob-2.1.1.tgz",
@@ -2169,6 +2185,15 @@
       "integrity": "sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==",
       "dev": true
     },
+    "is-wsl": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/is-wsl/-/is-wsl-2.2.0.tgz",
+      "integrity": "sha512-fKzAra0rGJUUBwGBgNkHZuToZcn+TtXHpeCgmkMJMMYx1sQDYaCSyjJBSCa2nH1DGm7s3n1oBnohoVTBaN7Lww==",
+      "dev": true,
+      "requires": {
+        "is-docker": "^2.0.0"
+      }
+    },
     "isbinaryfile": {
       "version": "4.0.10",
       "resolved": "https://registry.npmjs.org/isbinaryfile/-/isbinaryfile-4.0.10.tgz",
@@ -2228,13 +2253,14 @@
         "yargs": "^16.1.1"
       }
     },
-    "karma-chrome-launcher": {
-      "version": "3.1.1",
-      "resolved": "https://registry.npmjs.org/karma-chrome-launcher/-/karma-chrome-launcher-3.1.1.tgz",
-      "integrity": "sha512-hsIglcq1vtboGPAN+DGCISCFOxW+ZVnIqhDQcCMqqCp+4dmJ0Qpq5QAjkbA0X2L9Mi6OBkHi2Srrbmm7pUKkzQ==",
+    "karma-firefox-launcher": {
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/karma-firefox-launcher/-/karma-firefox-launcher-2.1.2.tgz",
+      "integrity": "sha512-VV9xDQU1QIboTrjtGVD4NCfzIH7n01ZXqy/qpBhnOeGVOkG5JYPEm8kuSd7psHE6WouZaQ9Ool92g8LFweSNMA==",
       "dev": true,
       "requires": {
-        "which": "^1.2.1"
+        "is-wsl": "^2.2.0",
+        "which": "^2.0.1"
       }
     },
     "karma-jasmine": {
@@ -2689,9 +2715,9 @@
       "dev": true
     },
     "which": {
-      "version": "1.3.1",
-      "resolved": "https://registry.npmjs.org/which/-/which-1.3.1.tgz",
-      "integrity": "sha512-HxJdYWq1MTIQbJ3nw0cqssHoTNU267KlrDuGZ1WYlxDStUtKUhOaJmh112/TZmHxxUfuJqPXSOm7tDyas0OSIQ==",
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
+      "integrity": "sha512-BLI3Tl1TW3Pvl70l3yq3Y64i+awpwXqsGBYWkkqMtnbXgrMD+yj7rhW0kuEDxzJaYXGjEW5ogapKNMEKNMjibA==",
       "dev": true,
       "requires": {
         "isexe": "^2.0.0"
diff --git a/guacamole-common-js/package.json b/guacamole-common-js/package.json
index 9c9d03fc1..f986f8038 100644
--- a/guacamole-common-js/package.json
+++ b/guacamole-common-js/package.json
@@ -2,7 +2,7 @@
   "description": "Dependencies to be installed by maven for running JS tests",
   "devDependencies": {
     "karma": "^6.4.1",
-    "karma-chrome-launcher": "^3.1.1",
+    "karma-firefox-launcher": "^2.1.2",
     "karma-jasmine": "^5.1.0"
   }
 }
diff --git a/guacamole-common-js/pom.xml b/guacamole-common-js/pom.xml
index 8cb4f3d88..ee969b183 100644
--- a/guacamole-common-js/pom.xml
+++ b/guacamole-common-js/pom.xml
@@ -37,6 +37,17 @@
         <relativePath>../</relativePath>
     </parent>
 
+    <properties>
+
+        <!--
+        The location where temporary files should be stored for communicating
+        between karma and firefox. The default location, /tmp, does not work
+        if firefox is installed via snap.
+        -->
+        <firefox.temp.dir>${project.basedir}/.tmp</firefox.temp.dir>
+        
+    </properties>
+
     <description>
         The base JavaScript API of the Guacamole project, providing JavaScript
         support for the Guacamole stack, including a full client
@@ -114,7 +125,27 @@
                 </executions>
             </plugin>
 
-            <!-- Unit test using Jasmin and PhantomJS -->
+            <!-- Ensure the firefox temp directory exists -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-antrun-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>createFirefoxTempdir</id>
+                        <phase>test-compile</phase>
+                        <configuration>
+                            <tasks>
+                                <mkdir dir="${firefox.temp.dir}"/>
+                            </tasks>
+                        </configuration>
+                        <goals>
+                            <goal>run</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <!-- Unit test using Jasmin and Firefox -->
             <plugin>
                 <groupId>com.github.eirslett</groupId>
                 <artifactId>frontend-maven-plugin</artifactId>
@@ -130,6 +161,11 @@
 
                     <!-- The location of the karma config file -->
                     <karmaConfPath>karma-ci.conf.js</karmaConfPath>
+
+                    <!-- Tell karma to use the custom temp directory -->
+                    <environmentVariables>
+                        <TMPDIR>${firefox.temp.dir}</TMPDIR>
+                    </environmentVariables>
                     
                 </configuration>
 
@@ -138,6 +174,7 @@
                     <!-- Install node.js and NPM before running tests -->
                     <execution>
                         <id>install node and npm</id>
+                        <phase>test-compile</phase>
                         <goals>
                             <goal>install-node-and-npm</goal>
                         </goals>
@@ -146,6 +183,7 @@
                     <!-- Install test dependencies -->
                     <execution>
                         <id>npm install</id>
+                        <phase>test-compile</phase>
                         <goals>
                             <goal>npm</goal>
                         </goals>
@@ -154,6 +192,7 @@
                     <!-- Run all tests non-interactively -->
                     <execution>
                         <id>run tests</id>
+                        <phase>test</phase>
                         <goals>
                             <goal>karma</goal>
                         </goals>