diff -r 523f64466a05 -r 519b46a8f4d2 mercurial/hgweb/hgweb_mod.py
--- a/mercurial/hgweb/hgweb_mod.py	Thu Jun 14 20:29:27 2018 +0900
+++ b/mercurial/hgweb/hgweb_mod.py	Thu Jun 14 13:44:42 2018 +0200
@@ -441,6 +441,8 @@
             res.headers['Content-Type'] = ctype
             return rctx.sendtemplate('error', error=pycompat.bytestr(e))
         except ErrorResponse as e:
+            for k, v in e.headers:
+                res.headers[k] = v
             res.status = statusmessage(e.code, pycompat.bytestr(e))
             res.headers['Content-Type'] = ctype
             return rctx.sendtemplate('error', error=pycompat.bytestr(e))