diff --git a/kernel/include/errno.h b/kernel/include/errno.h
index efd5e4f8..29e65eae 100644
--- a/kernel/include/errno.h
+++ b/kernel/include/errno.h
@@ -5,6 +5,7 @@
 #define ENOEXEC 8
 #define EBADF 9
 #define ENOMEM 12
+#define EFAULT 14
 #define EISDIR 21
 #define EINVAL 22
 #define EMFILE 24
diff --git a/kernel/src/sys/exec.cpp b/kernel/src/sys/exec.cpp
index 8d561dea..e9db4387 100644
--- a/kernel/src/sys/exec.cpp
+++ b/kernel/src/sys/exec.cpp
@@ -14,7 +14,7 @@ void sys_exec(Context* context, const char* pathname)
 {
     if (!pathname)
     {
-        context->rax = -EINVAL; // FIXME: This should probably return EFAULT.
+        context->rax = -EFAULT;
         return;
     }
 
diff --git a/kernel/src/sys/stdio.cpp b/kernel/src/sys/stdio.cpp
index bf716d5f..1d188489 100644
--- a/kernel/src/sys/stdio.cpp
+++ b/kernel/src/sys/stdio.cpp
@@ -66,8 +66,8 @@ void sys_write(Context* context, int fd, size_t size, const char* addr)
 {
     if (!addr)
     {
-        STDIO_FAIL(write, EINVAL);
-        context->rax = -EINVAL; // FIXME: This should probably return EFAULT.
+        STDIO_FAIL(write, EFAULT);
+        context->rax = -EFAULT;
         return;
     }
     if (fd >= TASK_MAX_FDS || fd < 0)
@@ -142,8 +142,8 @@ void sys_read(Context* context, int fd, size_t size, char* buffer)
 {
     if (!buffer)
     {
-        STDIO_FAIL(read, EINVAL);
-        context->rax = -EINVAL; // FIXME: This should probably return EFAULT.
+        STDIO_FAIL(read, EFAULT);
+        context->rax = -EFAULT;
         return;
     }
     if (fd >= TASK_MAX_FDS || fd < 0)
diff --git a/libs/libc/include/errno.h b/libs/libc/include/errno.h
index e5553588..deef29b7 100644
--- a/libs/libc/include/errno.h
+++ b/libs/libc/include/errno.h
@@ -9,6 +9,7 @@ extern int errno;
 #define ENOEXEC 8 // Exec format error
 #define EBADF 9   // Bad file descriptor
 #define ENOMEM 12 // Cannot allocate memory
+#define EFAULT 14 // Bad address
 #define EISDIR 21 // Is a directory
 #define EINVAL 22 // Invalid argument
 #define EMFILE 24 // Too many open files
diff --git a/libs/libc/src/string.cpp b/libs/libc/src/string.cpp
index 82bf0e04..93b1ae46 100644
--- a/libs/libc/src/string.cpp
+++ b/libs/libc/src/string.cpp
@@ -128,6 +128,7 @@ extern "C"
         case EMFILE: return "Too many open files";
         case EISDIR: return "Is a directory";
         case ENOEXEC: return "Exec format error";
+        case EFAULT: return "Bad address";
         case 0: return "Success";
         default: return (char*)(unsigned long int)err;
         }