Executive brief
Copyparty, a file-sharing and streaming application, contains an authorization flaw that allows a user with a valid file-access key to escalate their permissions and read an entire folder. This only affects deployments that explicitly enable both file-level and directory-level access controls simultaneously. An authenticated attacker could circumvent access restrictions and read files they should not have permission to access.
Technical details
The vulnerability is a type of authorization bypass (CWE-863) affecting Copyparty's access-control mechanism. When both filekeys (file-level access tokens) and dirkeys (directory-level access tokens) are enabled on the same volume via volflag configuration, an attacker with a valid filekey can manipulate it to be accepted as a dirkey, escalating their permissions from single-file access to full directory read access. The attack requires network access and authentication (a valid filekey), with no additional user interaction needed. The vulnerability affects Copyparty versions before 1.20.17, which contains the fix. Both filekey and dirkey features are disabled by default, limiting the affected deployment surface.
Affected products
- 9001 Copyparty < 1.20.17
Timeline
- 2026-07-06: disclosed: Initial disclosure
- 2026-07-06: patched: Version 1.20.17 released with fix
- 2026-08-18: advisory: Published to GitHub Advisory Database