diff --git a/plugin-manager/src/main/kotlin/com/itsaky/androidide/plugins/manager/services/IdeCommandServiceImpl.kt b/plugin-manager/src/main/kotlin/com/itsaky/androidide/plugins/manager/services/IdeCommandServiceImpl.kt
index 09df1d092c..23072e7655 100644
--- a/plugin-manager/src/main/kotlin/com/itsaky/androidide/plugins/manager/services/IdeCommandServiceImpl.kt
+++ b/plugin-manager/src/main/kotlin/com/itsaky/androidide/plugins/manager/services/IdeCommandServiceImpl.kt
@@ -14,12 +14,15 @@ import kotlinx.coroutines.Job
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.emptyFlow
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withTimeout
 import java.io.BufferedReader
 import java.io.File
+import java.io.IOException
 import java.io.InputStreamReader
+import java.nio.file.InvalidPathException
 import java.util.UUID
 import java.util.concurrent.ConcurrentHashMap
 
@@ -44,24 +47,43 @@ class IdeCommandServiceImpl internal constructor(
 			when (spec) {
 				// Through the tooling server, never ./gradlew: a second daemon doubles Gradle's memory
 				// on the device, and its output would never reach the Build Output pane.
-				is CommandSpec.GradleTask -> GradleTaskExecution(executionId, spec, gradleTaskRunner, timeoutMs)
+				is CommandSpec.GradleTask -> {
+					GradleTaskExecution(executionId, spec, gradleTaskRunner, timeoutMs)
+				}
 
-				is CommandSpec.ShellCommand -> CommandExecutionImpl(executionId, shellProcess(spec), timeoutMs)
+				is CommandSpec.ShellCommand -> {
+					val workDir =
+						try {
+							resolvePluginWorkingDirectory(pluginId, projectRootProvider(), spec.workingDirectory)
+						} catch (e: InvalidPathException) {
+							return RejectedCommandExecution(executionId, "Invalid working directory: ${e.message}")
+						} catch (e: IOException) {
+							return RejectedCommandExecution(executionId, "Invalid working directory: ${e.message}")
+						}
+					val processBuilder =
+						try {
+							shellProcess(spec, workDir)
+						} catch (e: IllegalArgumentException) {
+							return RejectedCommandExecution(executionId, "Invalid environment: ${e.message}")
+						}
+					CommandExecutionImpl(executionId, processBuilder, timeoutMs)
+				}
 			}
 		runningCommands[executionId] = execution
 		execution.start { runningCommands.remove(executionId) }
 		return execution
 	}
 
-	private fun shellProcess(spec: CommandSpec.ShellCommand): ProcessBuilder {
-		val workDir = resolvePluginWorkingDirectory(pluginId, projectRootProvider(), spec.workingDirectory)
-		return ProcessBuilder(listOf(spec.executable) + spec.arguments).apply {
+	private fun shellProcess(
+		spec: CommandSpec.ShellCommand,
+		workDir: File?,
+	): ProcessBuilder =
+		ProcessBuilder(listOf(spec.executable) + spec.arguments).apply {
 			workDir?.let { directory(it) }
 			environment().putAll(spec.environment)
 			redirectErrorStream(false)
 			TermuxProcessEnvironment.applyTo(environment(), appFilesDir)
 		}
-	}
 
 	override fun isCommandRunning(executionId: String): Boolean = runningCommands[executionId]?.isRunning() == true
 
@@ -224,3 +246,16 @@ private class CommandExecutionImpl(
 		private const val MAX_OUTPUT_BYTES = 10 * 1024 * 1024
 	}
 }
+
+private class RejectedCommandExecution(
+	override val executionId: String,
+	error: String,
+) : CommandExecution {
+	private val result = CommandResult.Failure(-1, "", "", error, 0)
+
+	override val output: Flow<CommandOutput> = emptyFlow()
+
+	override suspend fun await(): CommandResult = result
+
+	override fun cancel() = Unit
+}
diff --git a/plugin-manager/src/test/kotlin/com/itsaky/androidide/plugins/manager/services/IdeCommandServiceImplTest.kt b/plugin-manager/src/test/kotlin/com/itsaky/androidide/plugins/manager/services/IdeCommandServiceImplTest.kt
new file mode 100644
index 0000000000..ecbb1c891d
--- /dev/null
+++ b/plugin-manager/src/test/kotlin/com/itsaky/androidide/plugins/manager/services/IdeCommandServiceImplTest.kt
@@ -0,0 +1,55 @@
+package com.itsaky.androidide.plugins.manager.services
+
+import com.google.common.truth.Truth.assertThat
+import com.itsaky.androidide.plugins.PluginPermission
+import com.itsaky.androidide.plugins.extensions.CommandResult
+import com.itsaky.androidide.plugins.extensions.CommandSpec
+import kotlinx.coroutines.runBlocking
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+
+class IdeCommandServiceImplTest {
+	@get:Rule
+	val tmp = TemporaryFolder()
+
+	private fun resultFor(workingDirectory: String): CommandResult =
+		resultFor(CommandSpec.ShellCommand("true", workingDirectory = workingDirectory))
+
+	private fun resultFor(spec: CommandSpec): CommandResult {
+		val projectRoot = tmp.newFolder("project")
+		val service =
+			IdeCommandServiceImpl(
+				pluginId = "test.plugin",
+				permissions = setOf(PluginPermission.SYSTEM_COMMANDS),
+				projectRootProvider = { projectRoot },
+				appFilesDir = tmp.newFolder("files"),
+			)
+		val execution = service.executeCommand(spec, 5_000)
+		return runBlocking { execution.await() }
+	}
+
+	@Test
+	fun `a working directory with a NUL character fails the command`() {
+		val result = resultFor("sub\u0000dir")
+
+		assertThat(result).isInstanceOf(CommandResult.Failure::class.java)
+		assertThat((result as CommandResult.Failure).error).startsWith("Invalid working directory")
+	}
+
+	@Test
+	fun `a working directory too long to resolve fails the command`() {
+		val result = resultFor("a/".repeat(3000))
+
+		assertThat(result).isInstanceOf(CommandResult.Failure::class.java)
+		assertThat((result as CommandResult.Failure).error).startsWith("Invalid working directory")
+	}
+
+	@Test
+	fun `an environment variable with a NUL character fails the command`() {
+		val result = resultFor(CommandSpec.ShellCommand("true", environment = mapOf("KEY" to "a\u0000b")))
+
+		assertThat(result).isInstanceOf(CommandResult.Failure::class.java)
+		assertThat((result as CommandResult.Failure).error).startsWith("Invalid environment")
+	}
+}