Headline
GHSA-5662-2rj7-f2v6: copyparty allows Regex Denial of Service (ReDoS) in the upload listing
Summary
The filter
parameter for the “Recent uploads” page allows arbitrary Regexes. If this feature is enabled (which is the default), an attacker can craft a filter which deadlocks the server.
PoC
https://127.0.0.1:3923/?ru&filter=(.+)+x
Impact
The server becomes fully inaccessible for a long time.
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.