diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c
index 0ace6035be..cdf78cdecc 100644
--- a/src/backend/access/brin/brin_minmax_multi.c
+++ b/src/backend/access/brin/brin_minmax_multi.c
@@ -2364,14 +2364,14 @@ brin_minmax_multi_distance_inet(PG_FUNCTION_ARGS)
 		unsigned char mask;
 		int			nbits;
 
-		nbits = lena - (i * 8);
+		nbits = Max(0, lena - (i * 8));
 		if (nbits < 8)
 		{
 			mask = (0xFF << (8 - nbits));
 			addra[i] = (addra[i] & mask);
 		}
 
-		nbits = lenb - (i * 8);
+		nbits = Max(0, lenb - (i * 8));
 		if (nbits < 8)
 		{
 			mask = (0xFF << (8 - nbits));
diff --git a/src/test/regress/expected/brin_multi.out b/src/test/regress/expected/brin_multi.out
index fbbfb6710c..861a06ef8c 100644
--- a/src/test/regress/expected/brin_multi.out
+++ b/src/test/regress/expected/brin_multi.out
@@ -351,6 +351,12 @@ VACUUM brintest_multi;  -- force a summarization cycle in brinidx
 insert into public.brintest_multi (float4col) values (real 'nan');
 insert into public.brintest_multi (float8col) values (real 'nan');
 UPDATE brintest_multi SET int8col = int8col * int4col;
+-- Test handling of inet netmasks with inet_minmax_multi_ops
+CREATE TABLE brin_test_inet (a inet);
+CREATE INDEX ON brin_test_inet USING brin (a inet_minmax_multi_ops);
+INSERT INTO brin_test_inet VALUES ('127.0.0.1/0');
+INSERT INTO brin_test_inet VALUES ('0.0.0.0/12');
+DROP TABLE brin_test_inet;
 -- Tests for brin_summarize_new_values
 SELECT brin_summarize_new_values('brintest_multi'); -- error, not an index
 ERROR:  "brintest_multi" is not an index
diff --git a/src/test/regress/sql/brin_multi.sql b/src/test/regress/sql/brin_multi.sql
index 49f26072ec..070455257c 100644
--- a/src/test/regress/sql/brin_multi.sql
+++ b/src/test/regress/sql/brin_multi.sql
@@ -357,6 +357,13 @@ insert into public.brintest_multi (float8col) values (real 'nan');
 
 UPDATE brintest_multi SET int8col = int8col * int4col;
 
+-- Test handling of inet netmasks with inet_minmax_multi_ops
+CREATE TABLE brin_test_inet (a inet);
+CREATE INDEX ON brin_test_inet USING brin (a inet_minmax_multi_ops);
+INSERT INTO brin_test_inet VALUES ('127.0.0.1/0');
+INSERT INTO brin_test_inet VALUES ('0.0.0.0/12');
+DROP TABLE brin_test_inet;
+
 -- Tests for brin_summarize_new_values
 SELECT brin_summarize_new_values('brintest_multi'); -- error, not an index
 SELECT brin_summarize_new_values('tenk1_unique1'); -- error, not a BRIN index