Summary

There is a denial of service vulnerability in the If-Match and If-None-Match header parsing component of Sinatra, if the etag method is used when constructing the response and you are using Ruby < 3.2.

Details

Carefully crafted input can cause If-Match and If-None-Match header parsing in Sinatra to take an unexpected amount of time, possibly resulting in a denial of service attack vector. This header is typically involved in generating the ETag header value. Any applications that use the etag method when generating a response are impacted if they are using Ruby below version 3.2.

Resources

https://github.com/sinatra/sinatra/issues/2120 (report) https://github.com/sinatra/sinatra/pull/2121 (fix) https://github.com/sinatra/sinatra/pull/1823 (older ReDoS vulnerability) https://bugs.ruby-lang.org/issues/19104 (fix in Ruby >= 3.2)

Sinatra is a domain-specific language for creating web applications in Ruby. An issue was discovered in Sinatra 2.0 before 2.2.3 and 3.0 before 3.0.4. An application is vulnerable to a reflected file download (RFD) attack that sets the Content-Disposition header of a response when the filename is derived from user-supplied input. Version 2.2.3 and 3.0.4 contain patches for this issue.

An issue was discovered in rack-protection/lib/rack/protection/pathtraversal.rb in Sinatra 2.x before 2.0.1 on Windows. Path traversal is possible via backslash characters.