commit 6f5715f1ae56eebb3e96845fc83c02cde10a9686
Author: Ken Hornstein <kenh@cmf.nrl.navy.mil>
Date:   Fri Feb 4 21:21:34 2022 -0500

    Perform better matching for EHLO keywords
    
    Previously we would look for EHLO keywords based on matching the
    prefix, but this caused to match "AUTH=" when looking for "AUTH".
    Tighten up the match algorithm so we only match on a full keyword.

--- a/mts/smtp/smtp.c
+++ b/mts/smtp/smtp.c
@@ -928,7 +928,12 @@ EHLOset (char *s)
 
     for (ehlo = EHLOkeys; *ehlo; ehlo++) {
 	ep = *ehlo;
-	if (has_prefix(ep, s)) {
+	/*
+	 * Make sure the character after the EHLO keyword is either
+	 * a NUL or a space; this makes sure we don't get tripped up
+	 * on things like AUTH= if we're looking for AUTH
+	 */
+	if (has_prefix(ep, s) && (ep[len] == '\0' || ep[len] == ' ')) {
 	    for (ep += len; *ep == ' '; ep++)
 		continue;
 	    return ep;
