diff --git a/user_channel/user_layer.cpp b/user_channel/user_layer.cpp
index ee147d8..ff1f965 100644
--- a/user_channel/user_layer.cpp
+++ b/user_channel/user_layer.cpp
@@ -74,13 +74,16 @@
 
 Cc ipmiUserSetUserName(const uint8_t userId, const char* userName)
 {
-    std::string newUser(userName, 0, ipmiMaxUserName);
+    size_t len = strnlen(userName, ipmiMaxUserName);
+    std::string newUser(userName, len);
     return getUserAccessObject().setUserName(userId, newUser);
 }
 
 Cc ipmiUserSetUserName(const uint8_t userId, const std::string& userName)
 {
-    std::string newUser(userName, 0, ipmiMaxUserName);
+    size_t len =
+        std::min(userName.size(), static_cast<size_t>(ipmiMaxUserName));
+    std::string newUser(userName, 0, len);
     return getUserAccessObject().setUserName(userId, newUser);
 }
 
diff --git a/user_channel/user_mgmt.cpp b/user_channel/user_mgmt.cpp
index 8c5a1bf..bf45db9 100644
--- a/user_channel/user_mgmt.cpp
+++ b/user_channel/user_mgmt.cpp
@@ -33,7 +33,9 @@
 #include <xyz/openbmc_project/Common/error.hpp>
 #include <xyz/openbmc_project/User/Common/error.hpp>
 
+#include <algorithm>
 #include <cerrno>
+#include <cstring>
 #include <fstream>
 #include <regex>
 #include <variant>
@@ -173,9 +175,8 @@
         size_t usrIndex = 1;
         for (; usrIndex <= ipmiMaxUsers; ++usrIndex)
         {
-            std::string curName(
-                reinterpret_cast<char*>(userData->user[usrIndex].userName), 0,
-                ipmiMaxUserName);
+            std::string curName =
+                safeUsernameString(userData->user[usrIndex].userName);
             if (userName == curName)
             {
                 break; // found the entry
@@ -219,14 +220,9 @@
             }
             case UserUpdateEvent::userRenamed:
             {
-                std::fill(
-                    static_cast<uint8_t*>(userData->user[usrIndex].userName),
-                    static_cast<uint8_t*>(userData->user[usrIndex].userName) +
-                        sizeof(userData->user[usrIndex].userName),
-                    0);
-                std::strncpy(
-                    reinterpret_cast<char*>(userData->user[usrIndex].userName),
-                    newUserName.c_str(), ipmiMaxUserName);
+                safeUsernameCopyToBuffer(
+                    userData->user[usrIndex].userName,
+                    sizeof(userData->user[usrIndex].userName), newUserName);
                 ipmiRenameUserEntryPassword(userName, newUserName);
                 break;
             }
@@ -717,8 +713,8 @@
     }
 
     ipmi::SecureString passwd;
-    passwd.assign(reinterpret_cast<const char*>(userPassword), 0,
-                  maxIpmi20PasswordSize);
+    size_t len = strnlen(userPassword, maxIpmi20PasswordSize);
+    passwd.assign(reinterpret_cast<const char*>(userPassword), len);
     int retval = pamUpdatePasswd(userName.c_str(), passwd.c_str());
 
     switch (retval)
@@ -752,8 +748,9 @@
         userLock{*userMutex};
     UserInfo* userInfo = getUserInfo(userId);
     std::string userName;
-    userName.assign(reinterpret_cast<char*>(userInfo->userName), 0,
-                    ipmiMaxUserName);
+
+    safeUsernameAssign(userName, userInfo->userName);
+
     if (userName.empty())
     {
         lg2::debug("User name not set / invalid");
@@ -855,8 +852,7 @@
         userLock{*userMutex};
     UserInfo* userInfo = getUserInfo(userId);
     std::string userName;
-    userName.assign(reinterpret_cast<char*>(userInfo->userName), 0,
-                    ipmiMaxUserName);
+    safeUsernameAssign(userName, userInfo->userName);
     if (userName.empty())
     {
         lg2::debug("User name not set / invalid");
@@ -905,9 +901,8 @@
     size_t usrIndex = 1;
     for (; usrIndex <= ipmiMaxUsers; ++usrIndex)
     {
-        std::string curName(
-            reinterpret_cast<char*>(usersTbl.user[usrIndex].userName), 0,
-            ipmiMaxUserName);
+        std::string curName =
+            safeUsernameString(usersTbl.user[usrIndex].userName);
         if (userName == curName)
         {
             break; // found the entry
@@ -929,8 +924,7 @@
         return ccParmOutOfRange;
     }
     UserInfo* userInfo = getUserInfo(userId);
-    userName.assign(reinterpret_cast<char*>(userInfo->userName), 0,
-                    ipmiMaxUserName);
+    safeUsernameAssign(userName, userInfo->userName);
     return ccSuccess;
 }
 
@@ -1018,9 +1012,9 @@
             return ccUnspecifiedError;
         }
 
-        std::memset(userInfo->userName, 0, sizeof(userInfo->userName));
-        std::memcpy(userInfo->userName,
-                    static_cast<const void*>(userName.data()), userName.size());
+        safeUsernameCopyToBuffer(userInfo->userName, sizeof(userInfo->userName),
+                                 userName);
+
         userInfo->userInSystem = true;
         for (size_t chIndex = 0; chIndex < ipmiMaxChannels; chIndex++)
         {
@@ -1045,14 +1039,9 @@
                        renameUserMethod, "PATH", userMgrObjBasePath);
             return ccUnspecifiedError;
         }
-        std::fill(static_cast<uint8_t*>(userInfo->userName),
-                  static_cast<uint8_t*>(userInfo->userName) +
-                      sizeof(userInfo->userName),
-                  0);
 
-        std::memset(userInfo->userName, 0, sizeof(userInfo->userName));
-        std::memcpy(userInfo->userName,
-                    static_cast<const void*>(userName.data()), userName.size());
+        safeUsernameCopyToBuffer(userInfo->userName, sizeof(userInfo->userName),
+                                 userName);
 
         ipmiRenameUserEntryPassword(oldUser, userName);
         userInfo->userInSystem = true;
@@ -1207,8 +1196,11 @@
                 "Corrupted IPMI user data file - invalid user info");
         }
         std::string userName = userInfo[jsonUserName].get<std::string>();
-        std::strncpy(reinterpret_cast<char*>(usersTbl.user[usrIndex].userName),
-                     userName.c_str(), ipmiMaxUserName);
+
+        // Fixed-width username buffer in struct
+        safeUsernameCopyToBuffer(usersTbl.user[usrIndex].userName,
+                                 sizeof(usersTbl.user[usrIndex].userName),
+                                 userName);
 
         std::vector<std::string> privilege =
             userInfo[jsonPriv].get<std::vector<std::string>>();
@@ -1309,9 +1301,8 @@
     for (size_t usrIndex = 1; usrIndex <= ipmiMaxUsers; ++usrIndex)
     {
         Json jsonUserInfo;
-        jsonUserInfo[jsonUserName] = std::string(
-            reinterpret_cast<char*>(usersTbl.user[usrIndex].userName), 0,
-            ipmiMaxUserName);
+        jsonUserInfo[jsonUserName] =
+            safeUsernameString(usersTbl.user[usrIndex].userName);
         std::vector<std::string> privilege(ipmiMaxChannels);
         std::vector<bool> ipmiEnabled(ipmiMaxChannels);
         std::vector<bool> linkAuthEnabled(ipmiMaxChannels);
@@ -1389,9 +1380,8 @@
     // user index 0 is reserved, starts with 1
     for (size_t usrIndex = 1; usrIndex <= ipmiMaxUsers; ++usrIndex)
     {
-        std::string curName(
-            reinterpret_cast<char*>(userData->user[usrIndex].userName), 0,
-            ipmiMaxUserName);
+        std::string curName =
+            safeUsernameString(userData->user[usrIndex].userName);
         if (userName == curName)
         {
             lg2::debug("Username {USER_NAME} exists", "USER_NAME", userName);
@@ -1410,8 +1400,11 @@
         lg2::error("No empty slots found");
         return false;
     }
-    std::strncpy(reinterpret_cast<char*>(userData->user[freeIndex].userName),
-                 userName.c_str(), ipmiMaxUserName);
+
+    safeUsernameCopyToBuffer(userData->user[freeIndex].userName,
+                             sizeof(userData->user[freeIndex].userName),
+                             userName);
+
     uint8_t priv =
         static_cast<uint8_t>(UserAccess::convertToIPMIPrivilege(sysPriv)) &
         privMask;
@@ -1433,14 +1426,10 @@
 {
     UsersTbl* userData = getUsersTblPtr();
 
-    std::string userName(
-        reinterpret_cast<char*>(userData->user[usrIdx].userName), 0,
-        ipmiMaxUserName);
+    std::string userName = safeUsernameString(userData->user[usrIdx].userName);
     ipmiClearUserEntryPassword(userName);
-    std::fill(static_cast<uint8_t*>(userData->user[usrIdx].userName),
-              static_cast<uint8_t*>(userData->user[usrIdx].userName) +
-                  sizeof(userData->user[usrIdx].userName),
-              0);
+    std::memset(userData->user[usrIdx].userName, 0,
+                sizeof(userData->user[usrIdx].userName));
     for (size_t chIndex = 0; chIndex < ipmiMaxChannels; ++chIndex)
     {
         userData->user[usrIdx].userPrivAccess[chIndex].privilege = privNoAccess;
@@ -1655,9 +1644,8 @@
             std::vector<std::string> usrGrps;
             std::string usrPriv;
 
-            std::string userName(
-                reinterpret_cast<char*>(userData->user[usrIdx].userName), 0,
-                ipmiMaxUserName);
+            std::string userName =
+                safeUsernameString(userData->user[usrIdx].userName);
             sdbusplus::message::object_path tempUserPath(userObjBasePath);
             tempUserPath /= userName;
             std::string usersPath(tempUserPath);
diff --git a/user_channel/user_mgmt.hpp b/user_channel/user_mgmt.hpp
index 74166c2..ebfec02 100644
--- a/user_channel/user_mgmt.hpp
+++ b/user_channel/user_mgmt.hpp
@@ -21,13 +21,41 @@
 #include <ipmid/api.hpp>
 #include <sdbusplus/bus.hpp>
 
+#include <algorithm>
 #include <cstdint>
+#include <cstring>
 #include <ctime>
 #include <variant>
 
 namespace ipmi
 {
 
+// Inline functions for safe username buffer operations
+inline size_t safeUsernameLength(const uint8_t* buf)
+{
+    return strnlen(reinterpret_cast<const char*>(buf), ipmiMaxUserName);
+}
+
+inline std::string safeUsernameString(const uint8_t* buf)
+{
+    return std::string(reinterpret_cast<const char*>(buf),
+                       safeUsernameLength(buf));
+}
+
+inline void safeUsernameAssign(std::string& str, const uint8_t* buf)
+{
+    size_t len = safeUsernameLength(buf);
+    str.assign(reinterpret_cast<const char*>(buf), len);
+}
+
+inline void safeUsernameCopyToBuffer(uint8_t* buf, size_t bufSize,
+                                     const std::string& str)
+{
+    std::memset(buf, 0, bufSize);
+    const size_t n = std::min(str.size(), bufSize);
+    std::memcpy(buf, str.data(), n);
+}
+
 using DbusUserPropVariant =
     std::variant<std::vector<std::string>, std::string, bool>;