Researchers disclose critical file takeover flaws in Penpot

Penpot’s developers have patched a pair of critical flaws in the open‑source UI/UX design tool, after researchers publicly disclosed the full bug details and a PoC exploit. The central vulnerability, tracked as GHSA-8qqw-wm58-45v7, is a file takeover bug with a CVSS around 9.9. It arises from missing authorisation checks in the Clojure backend during the import-binfile operation, where the server validates edit rights only for the caller’s project, not for the target file-id.

As a result, an authenticated attacker can overwrite a victim’s file data and transfer ownership to their own project, effectively stealing and replacing the design file. A separate but related public report documents a WebSocket flaw (CVSS 7.7) where subscribe-file and subscribe-team streams lack proper access checks on file or team UUIDs, enabling any logged‑in user to view live edits, role changes and cursor movements.

The issues affect Penpot servers running multi‑user configurations dating from version 1.20 onward, with all builds before 2.18.0 vulnerable to the file‑import cross‑team attack. The maintainers have addressed both problems in version 2.18.0, via two merged pull requests: 10994 removes the unsafe file‑id field from the import-binfile schema, and 11069 adds strict access checks to WebSocket streams. Public disclosure of the PoC exploit has prompted urgent guidance for admins to upgrade to Penpot 2.18.0.

Until patched, self‑hosted instances should disable open user sign‑ups and restrict network access to trusted staff, while operators are advised to inspect logs for unexpected project‑id changes across teams. The vulnerability disclosures credit security researcher Louis Sanchez of Voke Cyber and the independent report by user rbrents3000. No active wild exploits have been confirmed.