diff --git a/lib_com/options.h b/lib_com/options.h
index ed3aa3cdb05c786ec4d70223222b75da24739930..bbea3aa1534059d14c1f9b80304d8ebe81ea7d42 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -168,6 +168,8 @@
 /* #################### Start NON-BE switches ############################ */
 /* any switch which is non-be wrt. TS 26.258 V3.0 */
 
+#define FIX_1543_MID_LSF_BITS                           /* VA: float issue 1543: Resolve "MSAN: use-of-uninitialized-value in lib_enc/lsf_enc.c:262:5 for EVS encoder" */
+
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_enc/acelp_core_enc.c b/lib_enc/acelp_core_enc.c
index 7c3f48f9f3b6faae1d5296c9c0a0f13a0df5f59a..f4442dc7c506aa9420f44b4265632dc656f4d0d8 100644
--- a/lib_enc/acelp_core_enc.c
+++ b/lib_enc/acelp_core_enc.c
@@ -371,6 +371,9 @@ ivas_error acelp_core_enc(
         nb_bits = 0;
         st->acelp_cfg.FEC_mode = 0;
         uc_two_stage_flag = 0;
+#ifdef FIX_1543_MID_LSF_BITS
+        st->acelp_cfg.mid_lsf_bits = -1;
+#endif
 
         if ( !nelp_mode && !ppp_mode )
         {