1 files changed, 4 insertions, 2 deletions

diff --git a/src/usr.bin/openssl/s_client.c b/src/usr.bin/openssl/s_client.c
index 2b05facc17..00b6f7178a 100644
--- a/src/usr.bin/openssl/s_client.c
+++ b/src/usr.bin/openssl/s_client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s_client.c,v 1.68 2026/02/01 08:45:31 martijn Exp $ */
+/* $OpenBSD: s_client.c,v 1.69 2026/05/09 14:16:37 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1314,7 +1314,9 @@ s_client_main(int argc, char **argv)
                 }
                 BIO_printf(sbio,
                     "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
-                seen = BIO_read(sbio, sbuf, BUFSIZZ);
+                seen = BIO_read(sbio, sbuf, BUFSIZZ - 1);
+                if (seen <= 0)
+                        goto shut;
                 sbuf[seen] = 0;
                 if (!strstr(sbuf, "<proceed"))
                         goto shut;