diff --git a/src/iss/arch/riscv_hart_m_p.h b/src/iss/arch/riscv_hart_m_p.h
index 7e40196..6f3834a 100644
--- a/src/iss/arch/riscv_hart_m_p.h
+++ b/src/iss/arch/riscv_hart_m_p.h
@@ -463,11 +463,13 @@ template <typename BASE, features_e FEAT> uint64_t riscv_hart_m_p<BASE, FEAT>::e
 #endif
     if((flags & 0xffffffff) != 0xffffffff) {
         if(trap_id) {
+            auto irq_str = cause < this->irq_str.size() ? this->irq_str.at(cause) : "Unknown";
             ILOG(disasslogger, logging::DEBUG,
-                 fmt::format("Interrupt with cause '{}' ({}) occurred  at address {}", this->irq_str[cause], cause, buffer.data()));
+                 fmt::format("Interrupt with cause '{}' ({}) occurred  at address {}", irq_str, cause, buffer.data()));
         } else {
+            auto irq_str = cause < this->trap_str.size() ? this->trap_str.at(cause) : "Unknown";
             ILOG(disasslogger, logging::DEBUG,
-                 fmt::format("Trap with cause '{}' ({}) occurred  at address {}", this->trap_str[cause], cause, buffer.data()));
+                 fmt::format("Trap with cause '{}' ({}) occurred  at address {}", irq_str, cause, buffer.data()));
         }
     }
     // reset trap state
diff --git a/src/iss/arch/riscv_hart_msu_vp.h b/src/iss/arch/riscv_hart_msu_vp.h
index 89ca0f4..c520be3 100644
--- a/src/iss/arch/riscv_hart_msu_vp.h
+++ b/src/iss/arch/riscv_hart_msu_vp.h
@@ -635,11 +635,13 @@ uint64_t riscv_hart_msu_vp<BASE, FEAT>::enter_trap(uint64_t flags, uint64_t addr
 #endif
     if((flags & 0xffffffff) != 0xffffffff) {
         if(trap_id) {
+            auto irq_str = cause < this->irq_str.size() ? this->irq_str.at(cause) : "Unknown";
             ILOG(disasslogger, logging::DEBUG,
-                 fmt::format("Interrupt with cause '{}' ({}) occurred  at address {}", this->irq_str[cause], cause, buffer.data()));
+                 fmt::format("Interrupt with cause '{}' ({}) occurred  at address {}", irq_str, cause, buffer.data()));
         } else {
+            auto irq_str = cause < this->trap_str.size() ? this->trap_str.at(cause) : "Unknown";
             ILOG(disasslogger, logging::DEBUG,
-                 fmt::format("Trap with cause '{}' ({}) occurred  at address {}", this->trap_str[cause], cause, buffer.data()));
+                 fmt::format("Trap with cause '{}' ({}) occurred  at address {}", irq_str, cause, buffer.data()));
         }
     }
     // reset trap this->state
diff --git a/src/iss/arch/riscv_hart_mu_p.h b/src/iss/arch/riscv_hart_mu_p.h
index 032ff17..46a044a 100644
--- a/src/iss/arch/riscv_hart_mu_p.h
+++ b/src/iss/arch/riscv_hart_mu_p.h
@@ -508,11 +508,13 @@ template <typename BASE, features_e FEAT> uint64_t riscv_hart_mu_p<BASE, FEAT>::
 #endif
     if((flags & 0xffffffff) != 0xffffffff) {
         if(trap_id) {
+            auto irq_str = cause < this->irq_str.size() ? this->irq_str.at(cause) : "Unknown";
             ILOG(disasslogger, logging::DEBUG,
-                 fmt::format("Interrupt with cause '{}' ({}) occurred  at address {}", this->irq_str[cause], cause, buffer.data()));
+                 fmt::format("Interrupt with cause '{}' ({}) occurred  at address {}", irq_str, cause, buffer.data()));
         } else {
+            auto irq_str = cause < this->trap_str.size() ? this->trap_str.at(cause) : "Unknown";
             ILOG(disasslogger, logging::DEBUG,
-                 fmt::format("Trap with cause '{}' ({}) occurred  at address {}", this->trap_str[cause], cause, buffer.data()));
+                 fmt::format("Trap with cause '{}' ({}) occurred  at address {}", irq_str, cause, buffer.data()));
         }
     }
     // reset trap state