diff --git b/lib/RT/User_Overlay.pm a/lib/RT/User_Overlay.pm
index 62c5176..b86a924 100755
--- b/lib/RT/User_Overlay.pm
+++ a/lib/RT/User_Overlay.pm
@@ -1079,7 +1079,7 @@ sub IsPassword {
         my $hash = MIME::Base64::decode_base64($stored);
         # The first 4 bytes are the salt, the rest is substr(SHA256,0,26)
         my $salt = substr($hash, 0, 4, "");
-        return substr(sha256($salt . Digest::MD5::md5($value)), 0, 26) eq $hash;
+        return substr(Digest::SHA::sha256($salt . Digest::MD5::md5($value)), 0, 26) eq $hash;
     } elsif (length $stored == 32) {
         # Hex nonsalted-md5
         return 0 unless Digest::MD5::md5_hex(encode_utf8($value)) eq $stored;