Remote code execution when handling telnet:// URI in KDE Konsole



Risk Critical
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2025-49091
CWE-ID CWE-20
Exploitation vector Network
Public exploit N/A
Vulnerable software
 konsole
Client/Desktop applications / Software for system administration

Vendor KDE.org

Security Bulletin

This security bulletin contains one critical risk vulnerability.

1) Input validation error

EUVDB-ID: #VU110673

Risk: Critical

CVSSv4.0: 4.8 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Red]

CVE-ID: CVE-2025-49091

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to insufficient validation of telnet://URL scheme. A remote attacker can trick the victim into clicking on a specially crafted URL and execute arbitrary console commands on the system with privileges of the current user. 

The vulnerability affects installations without telnet client installed. 

Mitigation

Install updates from vendor's website.

As a temporary solution you can install the telnet client, or delete the file:
/usr/share/applications/ktelnetservice6.desktop

Vulnerable software versions

konsole: 20.03.80 - 25.04.1

CPE2.3 External links

https://kde.org/info/security/advisory-20250609-1.txt


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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