Index: rulesrc/sandbox/kb/20_header.cf
===================================================================
--- rulesrc/sandbox/kb/20_header.cf	(revision 1178825)
+++ rulesrc/sandbox/kb/20_header.cf	(working copy)
@@ -34,6 +34,8 @@
 #       space that was showing up in header rules.  For 3.2.x releases the
 #       pattern must be changed to /^ \t/.
 
-header   KB_DATE_CONTAINS_TAB  Date:raw =~ /^\t/
+header   __KB_DATE_CONTAINS_TAB  Date:raw =~ /^\t/
+meta     KB_DATE_CONTAINS_TAB  __KB_DATE_CONTAINS_TAB && !__ML_TURNS_SP_TO_TAB 
+
 meta     KB_FAKED_THE_BAT      (__THEBAT_MUA && KB_DATE_CONTAINS_TAB)
 
Index: rulesrc/sandbox/hege/20_hk.cf
===================================================================
--- rulesrc/sandbox/hege/20_hk.cf	(revision 1178825)
+++ rulesrc/sandbox/hege/20_hk.cf	(working copy)
@@ -111,7 +111,9 @@
 score		HK_PNISES		1
 
 # From Mike Cappella
-header		TAB_IN_FROM		From:raw =~ /^\t/s
+header		__TAB_IN_FROM		From:raw =~ /^\t/s
+describe	__TAB_IN_FROM		From starts with a tab
+meta		TAB_IN_FROM		__TAB_IN_FROM && !__ML_TURNS_SP_TO_TAB 
 describe	TAB_IN_FROM		From starts with a tab
 
 
Index: rules/20_head_tests.cf
===================================================================
--- rules/20_head_tests.cf	(revision 1178825)
+++ rules/20_head_tests.cf	(working copy)
@@ -418,6 +418,10 @@
 meta     __VIA_ML  __ML1 || __ML2 || __ML3 || __ML4 || __ML5
 describe __VIA_ML  Mail from a mailing list
 
+# some clueless mailing lists are replacing a leading space by a TAB
+# in header fields From, To, Cc, Date (Bug 6429)
+header   __ML_TURNS_SP_TO_TAB  List-Id =~ /(^<|\.)vger\.kernel\.org>$/i
+describe __ML_TURNS_SP_TO_TAB  A mailing list changing a space to TAB
 
 # must keep it in sync with http://www.iana.org/assignments/ipv4-address-space/
 header RCVD_ILLEGAL_IP		X-Spam-Relays-Untrusted =~ / (?:by|ip)=(?=\d+\.\d+\.\d+\.\d+ )(?:0|2(?:2[4-9]|[3-5]\d)|192\.0\.2|198\.51\.100|203\.0\.113)\./