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Medium · 6.9 CVE-2026-30796 EUVD-2026-9836GHSA-v69h-c25q-f3jf

RustDesk Client Transmits Preset Address Book Password Verbatim in Heartbeat Sync

Published Mar 5, 2026 · Updated Jul 19, 2026 · Assigned by VULSec

Description

Cleartext Transmission of Sensitive Information, Insufficiently Protected Credentials vulnerability in rustdesk-client RustDesk Client rustdesk-client on Windows, MacOS, Linux, iOS, Android (Address book sync, Heartbeat sync loop modules) allows Sniffing Attacks.

The client places the preset address-book password verbatim into the heartbeat sync JSON body (src/hbbs_http/sync.rs). Over an intact HTTPS session it is not exposed in transit, but it is a reusable shared secret rather than a zero-knowledge proof, so it is recovered by any party that becomes the API endpoint - under the re-homed/rogue API server (CVE-2026-30797) - and the leaked credential then authorizes the server-side address book.

This vulnerability is associated with program files src/hbbs_http/sync.rs and program routines heartbeat sync body builder (emits preset-address-book-password).

This issue affects RustDesk Client: through 1.4.8.

Affected products

VendorProductAffectedFixed
rustdesk-client RustDesk Client ≤ 1.4.8 —

References