{"id":"CVE-2026-30789","summary":"RustDesk Auth Proof Uses Server-Controlled Salt/Challenge and Fast Double-SHA256, Enabling Offline Brute-Force","details":"Use of Password Hash With Insufficient Computational Effort, Improper Restriction of Excessive Authentication Attempts vulnerability in rustdesk-client RustDesk Client rustdesk-client on Windows, MacOS, Linux, iOS, Android (Client login, peer authentication modules) allows Password Brute Forcing.\n\nThe authentication proof is SHA256(SHA256(password + salt) + challenge), where both the salt and the challenge are generated entirely by the server with no client-side nonce, and the hash uses no slow key-derivation function. A rogue or on-path API/relay server (see CVE-2026-30794 / CVE-2026-30797) can issue a chosen salt and challenge, capture the resulting proof, and recover the password offline. The capture-replay claim (CWE-294) is withdrawn: the challenge is regenerated per connection (challenge = Config::get_auto_password(6)), so a captured proof is not replayable against the legitimate server. The 1.4.7 OTP brute-force limiter and the existing LOGIN_FAILURES counter constrain only ONLINE attempts and do not address offline recovery.\n\nThis vulnerability is associated with program files src/client.rs and program routines handle_hash(), handle_login_from_ui() (login proof construction).\n\nThis issue affects RustDesk Client: through 1.4.8.","modified":"2026-07-15T01:49:02.171493522Z","published":"2026-03-05T15:41:51.417Z","database_specific":{"cna_assigner":"VULSec","cwe_ids":["CWE-916"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/30xxx/CVE-2026-30789.json"},"references":[{"type":"WEB","url":"https://github.com/rustdesk/rustdesk,https://github.com/rustdesk/hbb_common"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/30xxx/CVE-2026-30789.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-30789"},{"type":"ADVISORY","url":"https://www.vulsec.org/"},{"type":"PACKAGE","url":"https://github.com/rustdesk/rustdesk/releases"},{"type":"ARTICLE","url":"https://rustdesk.com/docs/en/client/"},{"type":"EVIDENCE","url":"https://docs.google.com/document/d/e/2PACX-1vSds6jjpd38oO_yIAyd1HYtKNUuea-I-ozAPpGhYI7QgAU-QGJ7D8a4rOZVj1vmiUXV1EcdRHf9aZAW/pub"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/rustdesk/rustdesk","events":[{"introduced":"0"},{"last_affected":"9ded8d6ab24779db3c9334f5a3d6a652b8425c4f"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"last_affected":"1.4.8"}],"source":"AFFECTED_FIELD"}}],"versions":["1.4.8","1.4.7","1.4.6","nightly","1.4.5","1.4.4","1.4.3","1.4.2","1.4.1","1.4.0","1.3.9","1.3.8","1.3.7","1.3.6","1.3.5","1.3.4","1.3.3","1.3.2","1.3.1","1.3.0","1.2.7","1.2.6","1.2.5","fdroid-version","1.2.4","1.2.3-2","1.2.3-1","1.2.3","1.2.2","1.2.1","1.2.0","1.1.9","1.1.8","1.1.3"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-30789.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"}]}