From bfcc0e26a367625df7db7165172a4f0846b39421 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 18 Jan 2026 22:22:44 -1000
Subject: [PATCH] [dfrobot_sen0395][pipsolar][sim800l][wl_134] Replace sprintf
 with snprintf/buf_append_printf (#13301)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 esphome/components/dfrobot_sen0395/commands.h          | 8 ++++----
 esphome/components/pipsolar/output/pipsolar_output.cpp | 2 +-
 esphome/components/sim800l/sim800l.cpp                 | 5 +++--
 esphome/components/wl_134/wl_134.cpp                   | 5 +++--
 4 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/esphome/components/dfrobot_sen0395/commands.h b/esphome/components/dfrobot_sen0395/commands.h
index cf3ba50be0..3b0551b184 100644
--- a/esphome/components/dfrobot_sen0395/commands.h
+++ b/esphome/components/dfrobot_sen0395/commands.h
@@ -75,8 +75,8 @@ class SetLatencyCommand : public Command {
 class SensorCfgStartCommand : public Command {
  public:
   SensorCfgStartCommand(bool startup_mode) : startup_mode_(startup_mode) {
-    char tmp_cmd[20] = {0};
-    sprintf(tmp_cmd, "sensorCfgStart %d", startup_mode);
+    char tmp_cmd[20];  // "sensorCfgStart " (15) + "0/1" (1) + null = 17
+    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "sensorCfgStart %d", startup_mode);
     cmd_ = std::string(tmp_cmd);
   }
   uint8_t on_message(std::string &message) override;
@@ -142,8 +142,8 @@ class SensitivityCommand : public Command {
   SensitivityCommand(uint8_t sensitivity) : sensitivity_(sensitivity) {
     if (sensitivity > 9)
       sensitivity_ = sensitivity = 9;
-    char tmp_cmd[20] = {0};
-    sprintf(tmp_cmd, "setSensitivity %d", sensitivity);
+    char tmp_cmd[20];  // "setSensitivity " (15) + "0-9" (1) + null = 17
+    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "setSensitivity %d", sensitivity);
     cmd_ = std::string(tmp_cmd);
   };
   uint8_t on_message(std::string &message) override;
diff --git a/esphome/components/pipsolar/output/pipsolar_output.cpp b/esphome/components/pipsolar/output/pipsolar_output.cpp
index ebfb9a7bbc..60f6342759 100644
--- a/esphome/components/pipsolar/output/pipsolar_output.cpp
+++ b/esphome/components/pipsolar/output/pipsolar_output.cpp
@@ -8,7 +8,7 @@ namespace pipsolar {
 static const char *const TAG = "pipsolar.output";
 
 void PipsolarOutput::write_state(float state) {
-  char tmp[10];
+  char tmp[16];
   snprintf(tmp, sizeof(tmp), this->set_command_, state);
 
   if (std::find(this->possible_values_.begin(), this->possible_values_.end(), state) != this->possible_values_.end()) {
diff --git a/esphome/components/sim800l/sim800l.cpp b/esphome/components/sim800l/sim800l.cpp
index e3edda0e72..251e18648b 100644
--- a/esphome/components/sim800l/sim800l.cpp
+++ b/esphome/components/sim800l/sim800l.cpp
@@ -1,4 +1,5 @@
 #include "sim800l.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include <cstring>
 
@@ -50,8 +51,8 @@ void Sim800LComponent::update() {
   } else if (state_ == STATE_RECEIVED_SMS) {
     // Serial Buffer should have flushed.
     // Send cmd to delete received sms
-    char delete_cmd[20];
-    sprintf(delete_cmd, "AT+CMGD=%d", this->parse_index_);
+    char delete_cmd[20];  // "AT+CMGD=" (8) + uint8_t (max 3) + null = 12 <= 20
+    buf_append_printf(delete_cmd, sizeof(delete_cmd), 0, "AT+CMGD=%d", this->parse_index_);
     this->send_cmd_(delete_cmd);
     this->state_ = STATE_CHECK_SMS;
     this->expect_ack_ = true;
diff --git a/esphome/components/wl_134/wl_134.cpp b/esphome/components/wl_134/wl_134.cpp
index 20a145d183..a589f71c84 100644
--- a/esphome/components/wl_134/wl_134.cpp
+++ b/esphome/components/wl_134/wl_134.cpp
@@ -1,4 +1,5 @@
 #include "wl_134.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 #include <cinttypes>
@@ -78,8 +79,8 @@ Wl134Component::Rfid134Error Wl134Component::read_packet_() {
            reading.id, reading.country, reading.isData ? "true" : "false", reading.isAnimal ? "true" : "false",
            reading.reserved0, reading.reserved1);
 
-  char buf[20];
-  sprintf(buf, "%03d%012lld", reading.country, reading.id);
+  char buf[20];  // "%03d" (3) + "%012" PRId64 (12) + null = 16 max
+  buf_append_printf(buf, sizeof(buf), 0, "%03d%012" PRId64, reading.country, reading.id);
   this->publish_state(buf);
   if (this->do_reset_) {
     this->set_timeout(1000, [this]() { this->publish_state(""); });