From c6c05f839595c5aff6f1cf930c2e0c8068b5caec Mon Sep 17 00:00:00 2001
From: Pierre Muller <pierre@freepascal.org>
Date: Mon, 13 Jan 2025 13:14:42 +0000
Subject: [PATCH] Check that index value is not below lower bound in
 TMessage.Valid method

---
 compiler/cmsgs.pas | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/compiler/cmsgs.pas b/compiler/cmsgs.pas
index 2e3769faae..b4ac19b784 100644
--- a/compiler/cmsgs.pas
+++ b/compiler/cmsgs.pas
@@ -461,8 +461,12 @@ begin
 end;
 
 function TMessage.Valid(nr:longint):boolean;
+var
+  i,j : longint;
 begin
-  result:=(nr div 1000<msgparts) and (nr mod 1000<msgidxmax[nr div 1000]) and assigned(msgidx[nr div 1000]^[nr mod 1000]);
+  i:=nr div 1000;
+  j:=nr mod 1000;
+  result:=(i>=low(msgstates)) and (i<msgparts) and (j<msgidxmax[i]) and assigned(msgidx[i]^[j]);
 end;
 
 procedure TMessage.ResetStates;