From 1f4136e76f2d414d0ec0b20f83d9e7333070db06 Mon Sep 17 00:00:00 2001
From: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>
Date: Tue, 28 Apr 2026 16:29:09 -0400
Subject: [PATCH] [pipsolar] Guard handle_qmod_ against empty message (#16085)

---
 esphome/components/pipsolar/pipsolar.cpp | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/esphome/components/pipsolar/pipsolar.cpp b/esphome/components/pipsolar/pipsolar.cpp
index c304d206c0..5123d8d9d3 100644
--- a/esphome/components/pipsolar/pipsolar.cpp
+++ b/esphome/components/pipsolar/pipsolar.cpp
@@ -433,13 +433,17 @@ void Pipsolar::handle_qpigs_(const char *message) {
 }
 
 void Pipsolar::handle_qmod_(const char *message) {
-  std::string mode;
-  char device_mode = char(message[1]);
   if (this->last_qmod_) {
     this->last_qmod_->publish_state(message);
   }
+  // QMOD response is "(M" where M is the device-mode character. Bail out if the
+  // message is shorter than 2 chars (e.g. empty error response from
+  // handle_poll_error_) — reading message[1] would otherwise be out of bounds.
+  if (message[0] == '\0' || message[1] == '\0')
+    return;
   if (this->device_mode_) {
-    mode = device_mode;
+    std::string mode;
+    mode = char(message[1]);
     this->device_mode_->publish_state(mode);
   }
 }