diff --git a/core/include/gnuradio-4.0/Block.hpp b/core/include/gnuradio-4.0/Block.hpp
index 904bfe15..4394c61b 100644
--- a/core/include/gnuradio-4.0/Block.hpp
+++ b/core/include/gnuradio-4.0/Block.hpp
@@ -514,9 +514,9 @@ class Block : public lifecycle::StateMachine<Derived>, //
         } else { // function not declared with 'noexcept' -> may throw
             try {
                 return std::forward<TFunction>(func)(std::forward<Args>(args)...);
-            } catch (gr::exception e) {
+            } catch (const gr::exception &e) {
                 emitErrorMessageIfAny(callingSite, std::unexpected(gr::Error(std::move(e))));
-            } catch (std::exception e) {
+            } catch (const std::exception &e) {
                 emitErrorMessageIfAny(callingSite, std::unexpected(gr::Error(e, location)));
             } catch (...) {
                 emitErrorMessageIfAny(callingSite, std::unexpected(gr::Error("unknown error", location)));
diff --git a/core/include/gnuradio-4.0/CircularBuffer.hpp b/core/include/gnuradio-4.0/CircularBuffer.hpp
index 2999870f..919e2594 100644
--- a/core/include/gnuradio-4.0/CircularBuffer.hpp
+++ b/core/include/gnuradio-4.0/CircularBuffer.hpp
@@ -81,9 +81,9 @@ class double_mapped_memory_resource : public std::pmr::memory_resource {
         for (int retry_attempt = 0; retry_attempt < 3; retry_attempt++) {
             try {
                 return do_allocate_internal(required_size, alignment);
-            } catch (std::system_error& e) { // explicitly caught for retry
+            } catch (const std::system_error& e) { // explicitly caught for retry
                 fmt::print("system-error: allocation failed (VERY RARE) '{}' - will retry, attempt: {}\n", e.what(), retry_attempt);
-            } catch (std::invalid_argument& e) { // explicitly caught for retry
+            } catch (const std::invalid_argument& e) { // explicitly caught for retry
                 fmt::print("invalid_argument: allocation failed (VERY RARE) '{}' - will retry, attempt: {}\n", e.what(), retry_attempt);
             }
         }
diff --git a/core/include/gnuradio-4.0/Tag.hpp b/core/include/gnuradio-4.0/Tag.hpp
index 0c2fcd0c..3a3042af 100644
--- a/core/include/gnuradio-4.0/Tag.hpp
+++ b/core/include/gnuradio-4.0/Tag.hpp
@@ -99,7 +99,7 @@ struct alignas(hardware_constructive_interference_size) Tag {
     get(const std::string &key) const noexcept {
         try {
             return map.at(key);
-        } catch (std::out_of_range &e) {
+        } catch (const std::out_of_range &e) {
             return std::nullopt;
         }
     }
@@ -108,7 +108,7 @@ struct alignas(hardware_constructive_interference_size) Tag {
     get(const std::string &key) noexcept {
         try {
             return map.at(key);
-        } catch (std::out_of_range &) {
+        } catch (const std::out_of_range &) {
             return std::nullopt;
         }
     }