Release 9.4.37 introduced a more precise implementation of RFC3986 with regards to URI decoding, together with some new compliance modes to optionally allow support of some URI that may have ambiguous interpretation within the Servlet specified API methods behaviours. The default mode allowed % encoded . characters to be excluded for URI normalisation, which is correct by the RFC, but is not assumed by common Servlet implementations. The default compliance mode allows requests with URIs that contain %2e
or %2e%2e
segments to access protected resources within the WEB-INF
directory. For example a request to /context/%2e/WEB-INF/web.xml
can retrieve the web.xml
file. This can reveal sensitive information regarding the implementation of a web application. Workarounds found by HttpCompliance mode RFC7230NOAMBIGUOUSURIS can be enabled by updating start.d/http.ini
to include: jetty.http.compliance=RFC7230NOAMBIGUOUSURIS.