diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 90aec85d6..f7f8708d1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -152,6 +152,8 @@ jobs:
           fi
           if [ "${{matrix.no_ubsan}}" = true ]; then
             set_env_var SOCI_NO_UBSAN 1
+          else
+            set_env_var UBSAN_OPTIONS print_stacktrace=1:halt_on_error=1
           fi
 
       - name: Setup tmate
diff --git a/include/soci/oracle/soci-oracle.h b/include/soci/oracle/soci-oracle.h
index 43cff3ec4..705751bd1 100644
--- a/include/soci/oracle/soci-oracle.h
+++ b/include/soci/oracle/soci-oracle.h
@@ -63,7 +63,7 @@ struct oracle_standard_into_type_backend : details::standard_into_type_backend
     OCIDefine *defnp_;
     sb2 indOCIHolder_;
     void *data_;
-    void *ociData_;
+    void *ociData_ = NULL;
     char *buf_;        // generic buffer
     details::exchange_type type_;
 
@@ -143,7 +143,7 @@ struct oracle_standard_use_type_backend : details::standard_use_type_backend
     OCIBind *bindp_;
     sb2 indOCIHolder_;
     void *data_;
-    void *ociData_;
+    void *ociData_ = NULL;
     bool readOnly_;
     char *buf_;        // generic buffer
     details::exchange_type type_;
diff --git a/src/backends/firebird/blob.cpp b/src/backends/firebird/blob.cpp
index b4e401b7b..e0e5f8456 100644
--- a/src/backends/firebird/blob.cpp
+++ b/src/backends/firebird/blob.cpp
@@ -59,7 +59,8 @@ std::size_t firebird_blob_backend::read_from_start(void * buf, std::size_t toRea
     // Ensure we don't read more than we have
     toRead = std::min(toRead, size - offset);
 
-    std::memcpy(buf, &data_[offset], toRead);
+    if (toRead)
+        std::memcpy(buf, &data_[offset], toRead);
 
     return toRead;
 }
@@ -121,7 +122,8 @@ void firebird_blob_backend::trim(std::size_t newLen)
 void firebird_blob_backend::writeBuffer(std::size_t offset,
                                       const void * buf, std::size_t toWrite)
 {
-    std::memcpy(data_.data() + offset, buf, toWrite);
+    if (toWrite)
+        std::memcpy(data_.data() + offset, buf, toWrite);
 }
 
 void firebird_blob_backend::open()
diff --git a/src/backends/oracle/standard-into-type.cpp b/src/backends/oracle/standard-into-type.cpp
index 89eb05936..5c0e78f19 100644
--- a/src/backends/oracle/standard-into-type.cpp
+++ b/src/backends/oracle/standard-into-type.cpp
@@ -391,15 +391,23 @@ void oracle_standard_into_type_backend::post_fetch(
 
 void oracle_standard_into_type_backend::clean_up()
 {
-    if (type_ == x_xmltype || type_ == x_longstring)
+    if (ociData_)
     {
-        free_temp_lob(statement_.session_, static_cast<OCILobLocator *>(ociData_));
-        ociData_ = NULL;
-    }
+        switch (type_)
+        {
+            case x_xmltype:
+            case x_longstring:
+                free_temp_lob(statement_.session_, static_cast<OCILobLocator *>(ociData_));
+                break;
+
+            case x_blob:
+                OCIDescriptorFree(ociData_, OCI_DTYPE_LOB);
+                break;
+
+            default:
+                throw soci_error("Internal error: OCI data used for unexpected type");
+        }
 
-    if (type_ == x_blob)
-    {
-        OCIDescriptorFree(ociData_, OCI_DTYPE_LOB);
         ociData_ = NULL;
     }
 
diff --git a/src/backends/oracle/standard-use-type.cpp b/src/backends/oracle/standard-use-type.cpp
index c9adf4422..8a2b64b04 100644
--- a/src/backends/oracle/standard-use-type.cpp
+++ b/src/backends/oracle/standard-use-type.cpp
@@ -710,14 +710,23 @@ void oracle_standard_use_type_backend::post_use(bool gotData, indicator *ind)
 
 void oracle_standard_use_type_backend::clean_up()
 {
-    if (type_ == x_xmltype || type_ == x_longstring)
-    {
-        free_temp_lob(statement_.session_, static_cast<OCILobLocator *>(ociData_));
-        ociData_ = NULL;
-    }
-    
-    if (type_ == x_blob)
+    if (ociData_)
     {
+        switch (type_)
+        {
+            case x_xmltype:
+            case x_longstring:
+                free_temp_lob(statement_.session_, static_cast<OCILobLocator *>(ociData_));
+                break;
+
+            case x_blob:
+                // We don't own the LOB locator, oracle_blob_backend does.
+                break;
+
+            default:
+                throw soci_error("Internal error: OCI data used for unexpected type");
+        }
+
         ociData_ = NULL;
     }