diff --git a/Foundation/Process.swift b/Foundation/Process.swift
index 201aaaf6ac..3f87d6caf4 100644
--- a/Foundation/Process.swift
+++ b/Foundation/Process.swift
@@ -860,7 +860,7 @@ open class Process: NSObject {
         for (new, old) in adddup2 {
             posix(_CFPosixSpawnFileActionsAddDup2(fileActions, old, new))
         }
-        for fd in addclose {
+        for fd in addclose.filter({ $0 >= 0 }) {
             posix(_CFPosixSpawnFileActionsAddClose(fileActions, fd))
         }
 
diff --git a/TestFoundation/TestProcess.swift b/TestFoundation/TestProcess.swift
index e33c056710..c203c5abde 100644
--- a/TestFoundation/TestProcess.swift
+++ b/TestFoundation/TestProcess.swift
@@ -696,6 +696,73 @@ class TestProcess : XCTestCase {
         }
     }
 
+    func test_pipeCloseBeforeLaunch() {
+        let process = Process()
+        let stdInput = Pipe()
+        let stdOutput = Pipe()
+
+        process.executableURL = xdgTestHelperURL()
+        process.arguments = ["--cat"]
+        process.standardInput = stdInput
+        process.standardOutput = stdOutput
+
+        let string = "Hello, World"
+        let stdInputPipe = stdInput.fileHandleForWriting
+        XCTAssertNoThrow(try stdInputPipe.write(XCTUnwrap(string.data(using: .utf8))))
+        stdInputPipe.closeFile()
+
+        XCTAssertNoThrow(try process.run())
+        process.waitUntilExit()
+
+        let stdOutputPipe = stdOutput.fileHandleForReading
+        do {
+            let readData = try XCTUnwrap(stdOutputPipe.readToEnd())
+            let readString = String(data: readData, encoding: .utf8)
+            XCTAssertEqual(string, readString)
+        } catch {
+            XCTFail("\(error)")
+        }
+    }
+
+    func test_multiProcesses() {
+        let source = Process()
+        source.executableURL = xdgTestHelperURL()
+        source.arguments = [ "--getcwd" ]
+
+        let cat1 = Process()
+        cat1.executableURL = xdgTestHelperURL()
+        cat1.arguments = [ "--cat" ]
+
+        let cat2 = Process()
+        cat2.executableURL = xdgTestHelperURL()
+        cat2.arguments = [ "--cat" ]
+
+        let pipe1 = Pipe()
+        source.standardOutput = pipe1
+        cat1.standardInput = pipe1
+
+        let pipe2 = Pipe()
+        cat1.standardOutput = pipe2
+        cat2.standardInput = pipe2
+
+        let pipe3 = Pipe()
+        cat2.standardOutput = pipe3
+
+        XCTAssertNoThrow(try source.run())
+        XCTAssertNoThrow(try cat1.run())
+        XCTAssertNoThrow(try cat2.run())
+        cat2.waitUntilExit()
+        cat1.waitUntilExit()
+        source.waitUntilExit()
+
+        do {
+            let data = try XCTUnwrap(pipe3.fileHandleForReading.readToEnd())
+            let pwd = String.init(decoding: data, as: UTF8.self).trimmingCharacters(in: CharacterSet(["\n", "\r"]))
+            XCTAssertEqual(pwd, FileManager.default.currentDirectoryPath.standardizePath())
+        } catch {
+            XCTFail("\(error)")
+        }
+    }
 
     static var allTests: [(String, (TestProcess) -> () throws -> Void)] {
         var tests = [
@@ -724,6 +791,8 @@ class TestProcess : XCTestCase {
             ("test_redirect_all_using_nil", test_redirect_all_using_nil),
             ("test_plutil", test_plutil),
             ("test_currentDirectory", test_currentDirectory),
+            ("test_pipeCloseBeforeLaunch", test_pipeCloseBeforeLaunch),
+            ("test_multiProcesses", test_multiProcesses),
         ]
 
 #if !os(Windows)