diff --git a/src/t_stream.c b/src/t_stream.c
index 00d1cbf1c..3f8cbfcfa 100644
--- a/src/t_stream.c
+++ b/src/t_stream.c
@@ -1922,11 +1922,21 @@ void xackCommand(client *c) {
         return;
     }
 
+    /* Start parsing the IDs, so that we abort ASAP if there is a syntax
+     * error: the return value of this command cannot be an error in case
+     * the client successfully acknowledged some messages, so it should be
+     * executed in a "all or nothing" fashion. */
+    for (int j = 3; j < c->argc; j++) {
+        streamID id;
+        if (streamParseStrictIDOrReply(c,c->argv[j],&id,0) != C_OK) return;
+    }
+
     int acknowledged = 0;
     for (int j = 3; j < c->argc; j++) {
         streamID id;
         unsigned char buf[sizeof(streamID)];
-        if (streamParseStrictIDOrReply(c,c->argv[j],&id,0) != C_OK) return;
+        if (streamParseStrictIDOrReply(c,c->argv[j],&id,0) != C_OK)
+            serverPanic("StreamID invalid after check. Should not be possible.");
         streamEncodeID(buf,&id);
 
         /* Lookup the ID in the group PEL: it will have a reference to the
diff --git a/tests/unit/type/stream-cgroups.tcl b/tests/unit/type/stream-cgroups.tcl
index a27e1f582..04661707b 100644
--- a/tests/unit/type/stream-cgroups.tcl
+++ b/tests/unit/type/stream-cgroups.tcl
@@ -93,6 +93,18 @@ start_server {
         assert {[r XACK mystream mygroup $id1 $id2] eq 1}
     }
 
+    test {XACK should fail if got at least one invalid ID} {
+        r del mystream
+        r xgroup create s g $ MKSTREAM
+        r xadd s * f1 v1
+        set c [llength [lindex [r xreadgroup group g c streams s >] 0 1]]
+        assert {$c == 1}
+        set pending [r xpending s g - + 10 c]
+        set id1 [lindex $pending 0 0]
+        assert_error "*Invalid stream ID specified*" {r xack s g $id1 invalid-id}
+        assert {[r xack s g $id1] eq 1}
+    }
+
     test {PEL NACK reassignment after XGROUP SETID event} {
         r del events
         r xadd events * f1 v1