Please report privately through GitHub: Security → Report a vulnerability.

Don't open a public issue for anything exploitable. Private reports go straight to the maintainer, stay unlisted until there's a fix, and can be turned into a published advisory afterwards.

Include what you have — a reproducer, the affected version (clippy status or dpkg -l clippy), your desktop environment and compositor. Expect a first response within about a week; this is a single-maintainer project, so please be patient rather than escalating publicly.

Only the latest release is supported. Fixes ship as a new version rather than as patches to older ones — see Releases.

Worth being explicit, because it shapes what counts as a vulnerability here.

Your clipboard history is sensitive by nature, and it is not encrypted at rest. Anything you copy — passwords out of a password manager, tokens, private keys — is written to ~/.local/share/clippy/history.db in plain text, along with images and copied files under the same directory. This is inherent to what a clipboard manager is, not a defect, but it means:

• The database is only as protected as your user account and home directory.
• Retention matters: Settings → History retention bounds how long a copied secret survives, and Clear history removes it now. Pinned items are kept until unpinned.
• Full-disk encryption is the right mitigation for the at-rest case.

If you'd rather a class of content were never recorded, that's a reasonable feature request — open an issue.

These are the parts where a report is most likely to be a real vulnerability:

• LAN clipboard sync (opt-in, off by default). Pairing uses a SPAKE2 password-authenticated key exchange keyed by the shown 6-digit code: neither side transmits the code or anything derived from it that an eavesdropper could offline-crack, and a wrong code cannot complete the handshake. Guessing is online-only and capped per pairing window. Paired peers are thereafter authenticated by long-term X25519 identity keys and traffic is encrypted with NaCl. The private key lives at ~/.local/share/clippy/identity.key (0600) and trusted peers in peers.json (0600). Pairing, key handling, replay, and anything that lets an unpaired device read or inject clipboard content are all in scope.
• The IPC control socket in $XDG_RUNTIME_DIR (0600). It accepts commands that can read and set the clipboard, so anything that widens access to it, or gets a command executed that shouldn't be, is in scope.
• The in-app updater. Settings → Check for updates fetches release metadata from the GitHub API over HTTPS and installs the downloaded .deb as root via pkexec. Integrity rests on TLS to GitHub and on PolicyKit prompting you; the package is not independently signature-checked by Clippy. Anything that could redirect, substitute, or tamper with what gets installed is a serious report. On Debian/Ubuntu, installing from the APT repository instead means apt verifies the repo's GPG signature, which is the stronger path.
• The X11/XWayland selection owner. Clippy runs a helper that owns the X11 CLIPBOARD selection and serves clip contents to requesting clients — by design, since that is how clips reach XWayland apps. Ways to make it serve something it shouldn't, or to a client that shouldn't get it, are in scope.
• Copied file handling. Recovering a file stages a copy under ~/.local/share/clippy/paste/; path traversal or symlink issues there are in scope.

• Clipboard contents being readable by other processes in your session. On both Wayland and X11 the clipboard is session-wide by design; any app you run can read it. That's the platform, not Clippy.
• The plaintext history database, as described above — unless you've found a way for something outside your user account to reach it.
• Compositor and toolkit bugs. Clipboard behaviour on Wayland depends heavily on the compositor, and some misbehaviour originates there — see docs/cosmic-comp-clipboard-bug.md for a worked example. Reports are still welcome; they may be redirected upstream.
• Anything requiring an attacker who already has your user account or root.