diff --git a/verif/env/uvme/uvme_cva6_cfg.sv b/verif/env/uvme/uvme_cva6_cfg.sv
index b757f5310..08a60b4e7 100644
--- a/verif/env/uvme/uvme_cva6_cfg.sv
+++ b/verif/env/uvme/uvme_cva6_cfg.sv
@@ -110,6 +110,7 @@ class uvme_cva6_cfg_c extends uvma_core_cntrl_cfg_c;
       ext_zifencei_supported == 1;
       ext_zicsr_supported    == 1;
       ext_zicond_supported   == 0;
+      ext_zcb_supported      == 1;
 
       mode_s_supported       == 0;
       mode_u_supported       == 0;
@@ -131,6 +132,12 @@ class uvme_cva6_cfg_c extends uvma_core_cntrl_cfg_c;
       nmi_addr_valid          == 1;
    }
 
+   constraint ext_const {
+      if (!ext_c_supported) {
+         ext_zcb_supported == 0;
+      }
+   }
+
    constraint default_cva6_boot_cons {
       (!mhartid_plusarg_valid)           -> (mhartid           == 'h0000_0000);
       (!mimpid_plusarg_valid)            -> (mimpid            == 'h0000_0000);