kde-connect: KDE Connect: Application crash via malicious device IDs

In KDE Connect before 1.33.0 on Android, malicious device IDs (sent via broadcast UDP) could cause an application crash.

The KDE Connect verification-code protocol before 2025-04-18 uses only 8 characters and therefore allows brute-force attacks. This affects KDE Connect before 1.33.0 on Android, KDE Connect before 25.04 on desktop, KDE Connect before 0.5 on iOS, Valent before 1.0.0.alpha.47, and GSConnect before 59.

kde-connect: KDE Connect: Unpairing of devices via invalid broadcast UDP packet

In KDE Connect before 1.33.0 on Android, a packet can be crafted that causes two paired devices to unpair. Specifically, it is an invalid discovery packet sent over broadcast UDP.

In the KDE Connect information-exchange protocol before 2025-04-18, a packet can be crafted to temporarily change the displayed information about a device, because broadcast UDP is used. This affects KDE Connect before 1.33.0 on Android, KDE Connect before 25.04 on desktop, KDE Connect before 0.5 on iOS, Valent before 1.0.0.alpha.47, and GSConnect before 59.

The KDE Connect protocol 8 before 2025-11-28 does not correlate device IDs across two packets. This affects KDE Connect before 25.12 on desktop, KDE Connect before 0.5.4 on iOS, KDE Connect before 1.34.4 on Android, GSConnect before 68, and Valent before 1.0.0.alpha.49.

In kdeconnect-kde (aka KDE Connect) before 20.08.2, an attacker on the local network could send crafted packets that trigger use of large amounts of CPU, memory, or network connection slots, aka a Denial of Service attack.