{"id":"CVE-2026-30789","aliases":["EUVD-2026-9834","GHSA-9qf7-q6gx-q652"],"status":"published","title":"RustDesk Auth Proof Uses Server-Controlled Salt/Challenge and Fast Double-SHA256, Enabling Offline Brute-Force","description":"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 The capture-replay claim (CWE-294) is withdrawn: the challenge is regenerated per connection (challenge = Config::get_auto_password(6)), so a captured proof is not replayable against the legitimate server.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.","severity":{"version":"4.0","score":5.7,"vector":"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00315,"percentile":0.24727,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-294","CWE-307","CWE-916"],"published":"2026-03-05T15:41:51Z","modified":"2026-11-08T02:47:32Z","products":[{"vendor":"rustdesk","product":"rustdesk"},{"vendor":"rustdesk-client","product":"rustdesk client"}],"references":[{"url":"https://rustdesk.com/docs/en/client/","tags":["technical-description","x_--config documentation","Product","article"]},{"url":"https://docs.google.com/document/d/e/2PACX-1vSds6jjpd38oO_yIAyd1HYtKNUuea-I-ozAPpGhYI7QgAU-QGJ7D8a4rOZVj1vmiUXV1EcdRHf9aZAW/pub","tags":["third-party-advisory","exploit","Exploit","Third Party Advisory","evidence"]},{"url":"https://www.vulsec.org/","tags":["vdb-entry","third-party-advisory","Not Applicable","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-30789","tags":["advisory"]},{"url":"https://rustdesk.com/docs/en/client"},{"url":"https://www.vulsec.org"},{"url":"https://github.com/advisories/GHSA-9qf7-q6gx-q652"},{"url":"https://github.com/rustdesk/rustdesk,https://github.com/rustdesk/hbb_common","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/30xxx/CVE-2026-30789.json","tags":["advisory"]},{"url":"https://github.com/rustdesk/rustdesk/releases","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-30789","title":"RustDesk Auth Proof Uses Server-Controlled Salt/Challenge and Fast Double-SHA256, Enabling Offline Brute-Force","description":"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.","status":"published","published":"2026-03-05T15:41:51.417Z","modified":"2026-06-22T13:16:30.794Z","cvss":[{"version":"4.0","score":5.7,"vector":"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","level":"medium","assessor":"cna"}],"cwes":["CWE-916"],"updated_at":"2026-11-02T13:44:07.200604Z"}],"euvd":[{"id":"EUVD-2026-9834","description":"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.","status":"published","published":"2026-03-05T15:41:51Z","modified":"2026-06-22T13:16:30Z","cvss":[{"version":"4.0","score":5.7,"vector":"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","level":"medium"}],"updated_at":"2026-11-02T18:20:35.26548Z"}],"ghsa":[{"id":"GHSA-9qf7-q6gx-q652","title":"Authentication Bypass by Capture-replay, Use of Password Hash With Insufficient Computational...","description":"Authentication Bypass by Capture-replay, Use of Password Hash With Insufficient Computational Effort vulnerability in rustdesk-client RustDesk Client rustdesk-client on Windows, MacOS, Linux, iOS, Android (Client login, peer authentication modules) allows Reusing Session IDs (aka Session Replay). This vulnerability is associated with program files src/client.Rs and program routines hash_password(), login proof construction.\n\nThis issue affects RustDesk Client: through 1.4.5.","status":"published","published":"2026-03-05T18:31:37Z","modified":"2026-06-22T12:32:00Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"critical"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-294","CWE-307","CWE-916"],"updated_at":"2026-11-02T15:08:55.672723Z"}],"nvd":[{"id":"CVE-2026-30789","description":"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.","status":"published","published":"2026-03-05T16:16:19.56Z","modified":"2026-06-22T14:16:36.63Z","cvss":[{"version":"4.0","score":5.7,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"}],"cwes":["CWE-916"],"updated_at":"2026-11-02T14:12:07.852448Z"}],"osv":[{"id":"CVE-2026-30789","title":"RustDesk Auth Proof Uses Server-Controlled Salt/Challenge and Fast Double-SHA256, Enabling Offline Brute-Force","description":"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.","status":"published","published":"2026-03-05T15:41:51.417Z","modified":"2026-11-08T02:47:32.695795284Z","cvss":[{"version":"4.0","score":5.7,"vector":"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","level":"medium"}],"cwes":["CWE-916"],"updated_at":"2026-11-08T02:57:14.556074Z"}]}}