diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 479ae8f96db..fc3a4c19e65 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -121,7 +121,12 @@ parse_publication_options(ParseState *pstate,
 			pubactions->pubtruncate = false;
 
 			*publish_given = true;
-			publish = defGetString(defel);
+
+			/*
+			 * SplitIdentifierString destructively modifies its input, so make
+			 * a copy so we don't modify the memory of the executing statement
+			 */
+			publish = pstrdup(defGetString(defel));
 
 			if (!SplitIdentifierString(publish, ',', &publish_list))
 				ereport(ERROR,
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 458418a249d..9ee8949e040 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -346,7 +346,11 @@ parse_output_parameters(List *options, PGOutputData *data)
 						 errmsg("conflicting or redundant options")));
 			publication_names_given = true;
 
-			if (!SplitIdentifierString(strVal(defel->arg), ',',
+			/*
+			 * Pass a copy of the DefElem->arg since SplitIdentifierString
+			 * modifies its input.
+			 */
+			if (!SplitIdentifierString(pstrdup(strVal(defel->arg)), ',',
 									   &data->publication_names))
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_NAME),