diff --git a/Sources/Fuzzilli/Execution/REPRL.swift b/Sources/Fuzzilli/Execution/REPRL.swift
index 22bb3c34f..005310ec8 100644
--- a/Sources/Fuzzilli/Execution/REPRL.swift
+++ b/Sources/Fuzzilli/Execution/REPRL.swift
@@ -24,8 +24,8 @@ public class REPRL: ComponentBase, ScriptRunner {
     /// Commandline arguments for the executable
     public private(set) var processArguments: [String]
 
-    /// Environment variables for the child process
-    private var env = [String]()
+    /// Environment variables for the child process. Shape: [(key, value)]
+    public private(set) var env = [(String, String)]()
 
     /// Number of script executions since start of child process
     private var execsSinceReset = 0
@@ -50,7 +50,7 @@ public class REPRL: ComponentBase, ScriptRunner {
         super.init(name: "REPRL")
 
         for (key, value) in processEnvironment {
-            env.append(key + "=" + value)
+            env.append((key, value))
         }
     }
 
@@ -61,7 +61,7 @@ public class REPRL: ComponentBase, ScriptRunner {
         }
 
         let argv = convertToCArray(processArguments)
-        let envp = convertToCArray(env)
+        let envp = convertToCArray(env.map({ $0 + "=" + $1 }))
 
         if reprl_initialize_context(reprlContext, argv, envp, /* capture stdout */ 1, /* capture stderr: */ 1) != 0 {
             logger.fatal("Failed to initialize REPRL context: \(String(cString: reprl_get_last_error(reprlContext)))")
@@ -76,7 +76,7 @@ public class REPRL: ComponentBase, ScriptRunner {
     }
 
     public func setEnvironmentVariable(_ key: String, to value: String) {
-        env.append(key + "=" + value)
+        env.append((key, value))
     }
 
     public func run(_ script: String, withTimeout timeout: UInt32) -> Execution {
diff --git a/Sources/Fuzzilli/Execution/ScriptRunner.swift b/Sources/Fuzzilli/Execution/ScriptRunner.swift
index 36bccf7e8..fcd408d1d 100644
--- a/Sources/Fuzzilli/Execution/ScriptRunner.swift
+++ b/Sources/Fuzzilli/Execution/ScriptRunner.swift
@@ -14,6 +14,7 @@
 
 public protocol ScriptRunner: Component {
     var processArguments: [String] { get }
+    var env: [(String, String)] { get }
 
     /// Executes a script, waits for it to complete, and returns the result.
     func run(_ script: String, withTimeout timeout: UInt32) -> Execution
diff --git a/Sources/Fuzzilli/Fuzzer.swift b/Sources/Fuzzilli/Fuzzer.swift
index 3be0dadb1..e9d10abf9 100644
--- a/Sources/Fuzzilli/Fuzzer.swift
+++ b/Sources/Fuzzilli/Fuzzer.swift
@@ -1013,7 +1013,9 @@ public class Fuzzer {
 
         // Wrap the executor in a JavaScriptTestRunner
         // If we can execute it standalone, it could inform us if any flags that were passed are incorrect, stale or conflicting.
-        let executor = JavaScriptExecutor(withExecutablePath: runner.processArguments[0], arguments: Array(runner.processArguments[1...]))
+        let executor = JavaScriptExecutor(
+            withExecutablePath: runner.processArguments[0],
+            arguments: Array(runner.processArguments[1...]), env: runner.env)
         do {
             let output = try executor.executeScript("", withTimeout: 300).output
             if output.lengthOfBytes(using: .utf8) > 0 {
diff --git a/Sources/Fuzzilli/Util/JavaScriptExecutor.swift b/Sources/Fuzzilli/Util/JavaScriptExecutor.swift
index 1f0ae1d50..4340c67ef 100644
--- a/Sources/Fuzzilli/Util/JavaScriptExecutor.swift
+++ b/Sources/Fuzzilli/Util/JavaScriptExecutor.swift
@@ -38,9 +38,12 @@ public class JavaScriptExecutor {
 
     let arguments: [String]
 
+    let env: [(String, String)]
+
     /// Depending on the type this constructor will try to find the requested shell or fail
-    public init?(type: ExecutorType = .any, withArguments maybeArguments: [String]? = nil) {
+    public init?(type: ExecutorType = .any, withArguments maybeArguments: [String]? = nil, withEnv maybeEnv: [(String, String)]? = nil) {
         self.arguments = maybeArguments ?? []
+        self.env = maybeEnv ?? []
         let path: String?
 
         switch type {
@@ -59,23 +62,24 @@ public class JavaScriptExecutor {
         self.executablePath = path!
     }
 
-    public init(withExecutablePath executablePath: String, arguments: [String]) {
+    public init(withExecutablePath executablePath: String, arguments: [String], env: [(String, String)]) {
         self.executablePath = executablePath
         self.arguments = arguments
+        self.env = env
     }
 
     /// Executes the JavaScript script using the configured engine and returns the stdout.
     public func executeScript(_ script: String, withTimeout timeout: TimeInterval? = nil) throws -> Result {
-        return try execute(executablePath, withInput: prefix + script.data(using: .utf8)!, withArguments: self.arguments, timeout: timeout)
+        return try execute(executablePath, withInput: prefix + script.data(using: .utf8)!, withArguments: self.arguments, withEnv: self.env, timeout: timeout)
     }
 
     /// Executes the JavaScript script at the specified path using the configured engine and returns the stdout.
     public func executeScript(at url: URL, withTimeout timeout: TimeInterval? = nil) throws -> Result {
         let script = try Data(contentsOf: url)
-        return try execute(executablePath, withInput: prefix + script, withArguments: self.arguments, timeout: timeout)
+        return try execute(executablePath, withInput: prefix + script, withArguments: self.arguments, withEnv: self.env, timeout: timeout)
     }
 
-    func execute(_ path: String, withInput input: Data = Data(), withArguments arguments: [String] = [], timeout maybeTimeout: TimeInterval? = nil) throws -> Result {
+    func execute(_ path: String, withInput input: Data = Data(), withArguments arguments: [String] = [], withEnv env: [(String, String)] = [], timeout maybeTimeout: TimeInterval? = nil) throws -> Result {
         let inputPipe = Pipe()
         let outputPipe = Pipe()
         let errorPipe = Pipe()
@@ -89,6 +93,8 @@ public class JavaScriptExecutor {
         // Close stdin
         try inputPipe.fileHandleForWriting.close()
 
+        let environment = ProcessInfo.processInfo.environment.merging(env, uniquingKeysWith: { _, new in new })
+
         // Execute the subprocess.
         let task = Process()
         task.standardOutput = outputPipe
@@ -96,6 +102,7 @@ public class JavaScriptExecutor {
         task.arguments = arguments + [url.path]
         task.executableURL = URL(fileURLWithPath: path)
         task.standardInput = inputPipe
+        task.environment = environment
         try task.run()
 
         var timedOut = false
diff --git a/Sources/Fuzzilli/Util/MockFuzzer.swift b/Sources/Fuzzilli/Util/MockFuzzer.swift
index a7bab9463..44feb77f4 100644
--- a/Sources/Fuzzilli/Util/MockFuzzer.swift
+++ b/Sources/Fuzzilli/Util/MockFuzzer.swift
@@ -26,6 +26,7 @@ struct MockExecution: Execution {
 
 class MockScriptRunner: ScriptRunner {
     var processArguments: [String] = []
+    var env: [(String, String)] = []
 
     func run(_ script: String, withTimeout timeout: UInt32) -> Execution {
         return MockExecution(outcome: .succeeded,