diff --git a/degesch.c b/degesch.c
index f92c86b..97b804e 100644
--- a/degesch.c
+++ b/degesch.c
@@ -4486,6 +4486,25 @@ irc_handle_isupport_prefix (struct server *s, char *value)
 	s->irc_channel_prefixes = xstrndup (prefixes, n_prefixes);
 }
 
+static void
+unescape_isupport_value (const char *value, struct str *output)
+{
+	const char *alphabet = "0123456789abcdef", *a, *b;
+	for (const char *p = value; *p; p++)
+	{
+		if (p[0] == '\\'
+		 && p[1] == 'x'
+		 && p[2] && (a = strchr (alphabet, tolower_ascii (p[2])))
+		 && p[3] && (b = strchr (alphabet, tolower_ascii (p[3]))))
+		{
+			str_append_c (output, (a - alphabet) << 4 | (b - alphabet));
+			p += 3;
+		}
+		else
+			str_append_c (output, *p);
+	}
+}
+
 static void
 irc_handle_rpl_isupport (struct server *s, const struct irc_message *msg)
 {
@@ -4499,8 +4518,14 @@ irc_handle_rpl_isupport (struct server *s, const struct irc_message *msg)
 		char *value = param + strcspn (param, "=");
 		if (*value) *value++ = '\0';
 
+		struct str value_unescaped;
+		str_init (&value_unescaped);
+		unescape_isupport_value (value, &value_unescaped);
+
 		if (!strcmp (param, "PREFIX"))
-			irc_handle_isupport_prefix (s, value);
+			irc_handle_isupport_prefix (s, value_unescaped.str);
+
+		str_free (&value_unescaped);
 	}
 
 	// TODO: initialize key_strxfrm according to server properties;