CVE-2025-66270: KDE Connect protocol · Authentication Bypass by Spoofing
Affects KDE Connect protocolSource CVE Database V5
Not known to be exploited · CVSS 4.7 Medium · fixed in 0.5.4 : update KDE Connect protocol when convenient.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.5.4, 1.34.4, 68
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 5 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade org.kde/kdeconnect-ios to 0.5.4; org.kde/kdeconnect-android to 1.34.4; gsconnect/gnome-shell-extension-gsconnect to 68.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Mavenorg.kde/kdeconnect-iospkg:maven/org.kde/kdeconnect-iosOther threats | Affected
| Fixed in
|
Mavenorg.kde/kdeconnect-androidpkg:maven/org.kde/kdeconnect-androidOther threats | Affected
| Fixed in
|
GitHubgsconnect/gnome-shell-extension-gsconnectpkg:github/gsconnect/gnome-shell-extension-gsconnectOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
To mitigate CVE-2025-66270, European organizations should: 1) Immediately inventory all devices running KDE Connect, GSConnect, or Valent to identify affected versions. 3) Implement network segmentation and restrict access to local networks where KDE Connect is used to limit potential attacker proximity. 4) Disable KDE Connect or related services on devices where it is not essential to reduce the attack surface. 5) Employ network monitoring tools to detect anomalous device communication patterns that could indicate spoofing attempts. 6) Educate users about the risks of connecting to untrusted networks or devices and encourage the use of VPNs or secure channels when using KDE Connect. 7) Consider alternative secure device synchronization tools if timely patching is not feasible. These steps go beyond generic advice by focusing on proactive inventory, network controls, and user awareness tailored to the KDE Connect ecosystem.
Description
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.
References
- invent.kde.org/network/kdeconnect-kde/-/commit/4e53bcdd5d4c28bd9fefd114b807ce35d7b3373e (opens in a new tab)
- invent.kde.org/network/kdeconnect-android/-/commit/675d2d24a1eb95d15d9e5bde2b7e2271d5ada6a9 (opens in a new tab)
- invent.kde.org/network/kdeconnect-ios/-/commit/6c003c22d04270cabc4b262d399c753d55cf9080 (opens in a new tab)
- github.com/GSConnect/gnome-shell-extension-gsconnect/commit/a38246deec0af50ae218cdc51db32cdd7eb145e3 (opens in a new tab)
- github.com/andyholmes/valent/commit/85f773124a67ed1add79e7465bb088ec667cccce (opens in a new tab)
- kde.org/info/security/advisory-20251128-1.txt (opens in a new tab)