Why do GPG keys expire at all?
Repository maintainers set expiry dates on their signing keys as a security practice. An expiry date limits the window in which a compromised key can do damage — if a private key leaks, an attacker can only use it until the expiry date passes.
What EXPKEYSIG actually means
When your package manager sees EXPKEYSIG, it found a valid signature made with a key that has simply passed its expiry date. The repository content itself is not necessarily unsafe — your system just can't currently verify it met the freshness bar the maintainer set.
The fix is always the same shape
- Get the renewed key (from a keyserver or the vendor's official URL)
- Import it into your package manager's trust store
- Refresh your package index
Use the Command Builder on the homepage to generate the exact commands for your distro.