diff --git a/src/shared/conf-parser.c b/src/shared/conf-parser.c
index ebbfa0d6c2..dbf5cc2fcd 100644
--- a/src/shared/conf-parser.c
+++ b/src/shared/conf-parser.c
@@ -194,6 +194,9 @@ static int parse_line(
                 if (!n)
                         return log_oom();
 
+                if (!string_is_safe(n))
+                        return log_syntax(unit, LOG_ERR, filename, line, SYNTHETIC_ERRNO(EBADMSG), "Bad characters in section header '%s'", l);
+
                 if (sections && !nulstr_contains(sections, n)) {
                         bool ignore;
                         const char *t;