orca.securityadvisory

Orca Security: Critical Unauthenticated RCE in Kopia Backup via SSH ProxyCommand Injection

Orca Security breaks down CVE-2026-45695 (CVSS 9.8), an unauthenticated RCE in the Kopia backup tool's HTTP server, affecting versions 0.22.3 and earlier. The flaw stems from Kopia's /api/v1/repo/exists endpoint splitting SFTP storage configuration fields on literal spaces without a proper tokenizer or quote handling, letting an attacker inject `-oProxyCommand=<cmd>` into the SSH command line when the server runs with --without-password and SFTP/external-SSH enabled — achieving code execution via a single crafted HTTP request. Fix is Kopia 0.23.0, which blocks starting with --insecure/--without-password on non-loopback interfaces; researcher Daniele Berardinelli reported it, tracked as GHSA-2q4c-3mrw-63c3.