diff --git a/CHANGELOG.md b/CHANGELOG.md
index b0c62d36..f555d472 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -64,6 +64,8 @@
 * When closing the window, send `SIGHUP` to the client application,
   before sending `SIGTERM`. The signal sequence is now `SIGHUP`, wait,
   `SIGTERM`, wait `SIGKILL`.
+* Crash when receiving a `DECRQSS` request with more than 2 bytes in
+  the `q` parameter.
 
 [1666]: https://codeberg.org/dnkl/foot/issues/1666
 
diff --git a/dcs.c b/dcs.c
index c4309459..19cce3c2 100644
--- a/dcs.c
+++ b/dcs.c
@@ -239,7 +239,7 @@ decrqss_put(struct terminal *term, uint8_t c)
         return;
 
     struct vt *vt = &term->vt;
-    if (vt->dcs.idx > 2)
+    if (vt->dcs.idx >= 2)
         return;
     vt->dcs.data[vt->dcs.idx++] = c;
 }