diff --git a/libc/calls/calls.h b/libc/calls/calls.h
index f6fc42a04..2604a1c54 100644
--- a/libc/calls/calls.h
+++ b/libc/calls/calls.h
@@ -84,6 +84,7 @@ int execv(const char *, char *const[]);
 int execve(const char *, char *const[], char *const[]);
 int execvp(const char *, char *const[]);
 int execvpe(const char *, char *const[], char *const[]);
+int fexecve(int, char *const[], char *const[]);
 int faccessat(int, const char *, int, uint32_t);
 int fadvise(int, uint64_t, uint64_t, int);
 int fchdir(int);
diff --git a/libc/calls/fexecve.c b/libc/calls/fexecve.c
new file mode 100644
index 000000000..224217cf0
--- /dev/null
+++ b/libc/calls/fexecve.c
@@ -0,0 +1,78 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/calls/syscall-sysv.internal.h"
+#include "libc/dce.h"
+#include "libc/fmt/itoa.h"
+#include "libc/intrin/asan.internal.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/intrin/likely.h"
+#include "libc/intrin/strace.internal.h"
+#include "libc/str/str.h"
+#include "libc/sysv/errfuns.h"
+
+int sys_fexecve(int, char *const[], char *const[]);
+
+/**
+ * Executes binary executable at file descriptor.
+ *
+ * This is only supported on Linux and FreeBSD. APE binaries currently
+ * aren't supported.
+ *
+ * @param fd is opened executable and current file position is ignored
+ * @return doesn't return on success, otherwise -1 w/ errno
+ * @raise ENOEXEC if file at `fd` isn't an assimilated ELF executable
+ * @raise ENOSYS on Windows, XNU, OpenBSD, NetBSD, and Metal
+ */
+int fexecve(int fd, char *const argv[], char *const envp[]) {
+  int rc;
+  size_t i;
+  if (!argv || !envp ||
+      (IsAsan() &&
+       (!__asan_is_valid_strlist(argv) || !__asan_is_valid_strlist(envp)))) {
+    rc = efault();
+  } else {
+#ifdef SYSDEBUG
+    if (UNLIKELY(__strace > 0)) {
+      kprintf(STRACE_PROLOGUE "fexecve(%d, {", fd);
+      for (i = 0; argv[i]; ++i) {
+        if (i) kprintf(", ");
+        kprintf("%#s", argv[i]);
+      }
+      kprintf("}, {");
+      for (i = 0; envp[i]; ++i) {
+        if (i) kprintf(", ");
+        kprintf("%#s", envp[i]);
+      }
+      kprintf("})\n");
+    }
+#endif
+    if (IsLinux()) {
+      char path[14 + 12];
+      FormatInt32(stpcpy(path, "/proc/self/fd/"), fd);
+      rc = __sys_execve(path, argv, envp);
+    } else if (IsFreebsd()) {
+      rc = sys_fexecve(fd, argv, envp);
+    } else {
+      rc = enosys();
+    }
+  }
+  STRACE("fexecve(%d) failed %d% m", fd, rc);
+  return rc;
+}
diff --git a/libc/sysv/calls/sys_fexecve.s b/libc/sysv/calls/sys_fexecve.s
new file mode 100644
index 000000000..3490a9ddb
--- /dev/null
+++ b/libc/sysv/calls/sys_fexecve.s
@@ -0,0 +1,2 @@
+.include "o/libc/sysv/macros.internal.inc"
+.scall sys_fexecve,0xffffff1ecfffffff,globl,hidden
diff --git a/libc/sysv/consts.sh b/libc/sysv/consts.sh
index 458f4b99c..0850d4bcd 100755
--- a/libc/sysv/consts.sh
+++ b/libc/sysv/consts.sh
@@ -204,7 +204,7 @@ syscon	open	O_NOFOLLOW_ANY				0			0x20000000		0			0			0			0			#
 syscon	open	O_SYNC					0x00101000		0x00000080		0x00000080		0x00000080		0x00000080		0			# bsd consensus
 syscon	open	O_NOCTTY				0x00000100		0x00020000		0x00008000		0x00008000		0x00008000		0			# used for remote viewing (default behavior on freebsd)
 syscon	open	O_NOATIME				0x00040000		0			0			0			0			0			# optimize away access time update
-syscon	open	O_EXEC					0			0			0x00040000		0			0x04000000		0			# it's specified by posix what does it mean
+syscon	open	O_EXEC					0x00200000		0			0x00040000		0			0x04000000		0			# open only for executing (POSIX.1 hack for when file mode is 0111); see fexecve(); O_PATH on Linux
 syscon	open	O_SEARCH				0			0			0x00040000		0			0x00800000		0			# it's specified by posix what does it mean
 syscon	open	O_DSYNC					0x00001000		0x00400000		0			0x00000080		0x00010000		0			#
 syscon	open	O_RSYNC					0x00101000		0			0			0x00000080		0x00020000		0			#
diff --git a/libc/sysv/consts/O_EXEC.s b/libc/sysv/consts/O_EXEC.s
index 2337014db..05a0ef1a8 100644
--- a/libc/sysv/consts/O_EXEC.s
+++ b/libc/sysv/consts/O_EXEC.s
@@ -1,2 +1,2 @@
 .include "o/libc/sysv/consts/syscon.internal.inc"
-.syscon open,O_EXEC,0,0,0x00040000,0,0x04000000,0
+.syscon open,O_EXEC,0x00200000,0,0x00040000,0,0x04000000,0
diff --git a/libc/sysv/syscalls.sh b/libc/sysv/syscalls.sh
index 17a4febab..0619c452c 100755
--- a/libc/sysv/syscalls.sh
+++ b/libc/sysv/syscalls.sh
@@ -673,7 +673,7 @@ scall	sys_bsdthread_register	0xfffffffff216efff	globl hidden
 #scall	extattr_set_file	0x169fff164fffffff	globl
 #scall	extattr_set_link	0x16ffff19cfffffff	globl
 #scall	extattrctl		0x168fff163fffffff	globl
-#scall	fexecve			0x1d1fff1ecfffffff	globl
+scall	sys_fexecve		0xffffff1ecfffffff	globl hidden
 #scall	ffclock_getcounter	0xffffff0f1fffffff	globl
 #scall	ffclock_getestimate	0xffffff0f3fffffff	globl
 #scall	ffclock_setestimate	0xffffff0f2fffffff	globl
diff --git a/test/libc/calls/fexecve_test.c b/test/libc/calls/fexecve_test.c
new file mode 100644
index 000000000..5afd0ec7a
--- /dev/null
+++ b/test/libc/calls/fexecve_test.c
@@ -0,0 +1,66 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/dce.h"
+#include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/testlib/subprocess.h"
+#include "libc/testlib/testlib.h"
+
+int fds[2];
+char buf[8];
+char testlib_enable_tmp_setup_teardown;
+
+TEST(execve, elfIsUnreadable_mayBeExecuted) {
+  if (IsWindows() || IsXnu()) return;
+  testlib_extract("/zip/echo", "echo", 0111);
+  ASSERT_SYS(0, 0, pipe2(fds, O_CLOEXEC));
+  SPAWN(vfork);
+  ASSERT_SYS(0, 1, dup2(4, 1));
+  ASSERT_SYS(
+      0, 0,
+      execve("echo", (char *const[]){"echo", "hi", 0}, (char *const[]){0}));
+  notpossible;
+  EXITS(0);
+  bzero(buf, 8);
+  ASSERT_SYS(0, 0, close(4));
+  ASSERT_SYS(0, 3, read(3, buf, 7));
+  ASSERT_SYS(0, 0, close(3));
+  ASSERT_STREQ("hi\n", buf);
+}
+
+TEST(fexecve, elfIsUnreadable_mayBeExecuted) {
+  if (!IsLinux() && !IsFreebsd()) return;
+  testlib_extract("/zip/echo", "echo", 0111);
+  ASSERT_SYS(0, 0, pipe2(fds, O_CLOEXEC));
+  SPAWN(vfork);
+  ASSERT_SYS(0, 1, dup2(4, 1));
+  ASSERT_SYS(0, 5, open("echo", O_EXEC | O_CLOEXEC));
+  if (IsFreebsd()) ASSERT_SYS(0, 1, lseek(5, 1, SEEK_SET));
+  ASSERT_SYS(0, 0,
+             fexecve(5, (char *const[]){"echo", "hi", 0}, (char *const[]){0}));
+  notpossible;
+  EXITS(0);
+  bzero(buf, 8);
+  ASSERT_SYS(0, 0, close(4));
+  ASSERT_SYS(0, 3, read(3, buf, 7));
+  ASSERT_SYS(0, 0, close(3));
+  ASSERT_STREQ("hi\n", buf);
+}
diff --git a/test/libc/calls/test.mk b/test/libc/calls/test.mk
index ff00f3200..861f419aa 100644
--- a/test/libc/calls/test.mk
+++ b/test/libc/calls/test.mk
@@ -88,6 +88,16 @@ o/$(MODE)/test/libc/calls/life-nomod.com.dbg:				\
 		$(APE_NO_MODIFY_SELF)
 	@$(APELINK)
 
+o/$(MODE)/test/libc/calls/fexecve_test.com.dbg:				\
+		$(TEST_LIBC_CALLS_DEPS)					\
+		o/$(MODE)/test/libc/calls/fexecve_test.o		\
+		o/$(MODE)/test/libc/calls/calls.pkg			\
+		o/$(MODE)/tool/build/echo.zip.o				\
+		$(LIBC_TESTMAIN)					\
+		$(CRT)							\
+		$(APE_NO_MODIFY_SELF)
+	@$(APELINK)
+
 o/$(MODE)/test/libc/calls/tiny64.elf.zip.o				\
 o/$(MODE)/test/libc/calls/life-nomod.com.zip.o				\
 o/$(MODE)/test/libc/calls/life-classic.com.zip.o: private		\
diff --git a/test/libc/zipos/open_test.c b/test/libc/zipos/open_test.c
index 25c8edbc7..d90e39be2 100644
--- a/test/libc/zipos/open_test.c
+++ b/test/libc/zipos/open_test.c
@@ -17,15 +17,14 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
-#include "libc/mem/mem.h"
 #include "libc/mem/gc.h"
+#include "libc/mem/mem.h"
 #include "libc/runtime/runtime.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/o.h"
 #include "libc/testlib/hyperion.h"
 #include "libc/testlib/testlib.h"
 #include "libc/thread/spawn.h"
-#include "libc/zipos/zipos.h"
 
 STATIC_YOINK("zip_uri_support");
 STATIC_YOINK("libc/testlib/hyperion.txt");