diff --git a/sections/cper-section-arm.c b/sections/cper-section-arm.c
index b56dc50..a1e9a2d 100644
--- a/sections/cper-section-arm.c
+++ b/sections/cper-section-arm.c
@@ -181,7 +181,8 @@
 		    strlen(*desc_string) + err_info_desc_i_len <
 			    SECTION_DESC_STRING_SIZE) {
 			strncat(*desc_string, err_info_desc_i,
-				err_info_desc_i_len);
+				SECTION_DESC_STRING_SIZE -
+					strlen(*desc_string) - 1);
 		} else {
 			cper_print_log(
 				"Error: Error info description string too long, not added to description string: %s\n",
diff --git a/sections/cper-section-nvidia.c b/sections/cper-section-nvidia.c
index c75bf8a..2882ad4 100644
--- a/sections/cper-section-nvidia.c
+++ b/sections/cper-section-nvidia.c
@@ -168,7 +168,8 @@
 	}
 
 	int property_desc_len = strlen(property_desc);
-	strncat(*desc_string, property_desc, property_desc_len);
+	strncat(*desc_string, property_desc,
+		SECTION_DESC_STRING_SIZE - strlen(*desc_string) - 1);
 	// We still want to get as much info as possible, just warn about truncation
 	if (property_desc_len + strlen(*desc_string) >=
 	    SECTION_DESC_STRING_SIZE) {