--- cyrus-imapd-2.2.6/imap/message.c.acceptinvalidfrom	2004-10-30 15:03:02.220642392 -0700
+++ cyrus-imapd-2.2.6/imap/message.c	2004-10-30 15:06:01.838336352 -0700
@@ -229,6 +229,8 @@
     int reject8bit = config_getswitch(IMAPOPT_REJECT8BIT);
     int munge8bit = config_getswitch(IMAPOPT_MUNGE8BIT);
     int inheader = 1, blankline = 1;
+    char is_from;
+    static const char * from_header = "From ";
 
     while (size) {
 	n = prot_read(from, buf, size > 4096 ? 4096 : size);
@@ -294,8 +296,20 @@
 	/* Check for valid header name */
 	if (sawnl && buf[0] != ' ' && buf[0] != '\t') {
 	    if (buf[0] == ':') return IMAP_MESSAGE_BADHEADER;
-	    for (p = (unsigned char *)buf; *p != ':'; p++) {
-		if (*p <= ' ') return IMAP_MESSAGE_BADHEADER;
+            p = (unsigned char *) buf;
+            if (*p == '>')
+                p++;
+            if (*p == from_header[0])
+                is_from = 0;
+            else
+                is_from = -1;
+            for (; *p != ':' && is_from < 5; p++) {
+                if (is_from > 0 && *p != from_header[is_from])
+                    is_from = -1;
+                if (is_from >= 0)
+                    is_from++;
+                else
+                    if (*p <= ' ') return IMAP_MESSAGE_BADHEADER;
 	    }
 	}