diff --git a/include/gmssl/kyber.h b/include/gmssl/kyber.h
index 2802441f..a5c41243 100644
--- a/include/gmssl/kyber.h
+++ b/include/gmssl/kyber.h
@@ -94,7 +94,7 @@ void kyber_poly_add(kyber_poly_t r, const kyber_poly_t a, const kyber_poly_t b);
 void kyber_poly_sub(kyber_poly_t r, const kyber_poly_t a, const kyber_poly_t b);
 
 
-int16_t zeta[256];
+extern int16_t zeta[256];
 
 void init_zeta(void);