diff --git a/src/exec.c b/src/exec.c
index 383a0c351..9e8021036 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -208,7 +208,7 @@ backchannel_cb(int fd, int what, void *v)
     debug_decl(backchannel_cb, SUDO_DEBUG_EXEC)
 
     /* read child status */
-    n = recv(fd, ec->cstat, sizeof(struct command_status), 0);
+    n = recv(fd, ec->cstat, sizeof(struct command_status), MSG_WAITALL);
     if (n != sizeof(struct command_status)) {
 	if (n == -1) {
 	    switch (errno) {
diff --git a/src/exec_pty.c b/src/exec_pty.c
index 278ec531f..aa55163bc 100644
--- a/src/exec_pty.c
+++ b/src/exec_pty.c
@@ -1141,7 +1141,7 @@ mon_backchannel_cb(int fd, int what, void *v)
     debug_decl(mon_backchannel_cb, SUDO_DEBUG_EXEC);
 
     /* read command from backchannel, should be a signal */
-    n = recv(fd, &cstmp, sizeof(cstmp), 0);
+    n = recv(fd, &cstmp, sizeof(cstmp), MSG_WAITALL);
     if (n != sizeof(cstmp)) {
 	if (n == -1) {
 	    if (errno == EINTR || errno == EAGAIN)