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Remote code execution in OpenConnect VPN client

Published: 2020-05-23
Severity Medium
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2020-12823
Exploitation vector Network
Public exploit N/A
Vulnerable software
OpenConnect VPN Client
Client/Desktop applications / Other client software

Vendor OpenConnect

Security Advisory

This security advisory describes one medium risk vulnerability.

1) Buffer overflow

Severity: Medium

CVSSv3: 6.5 [CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2020-12823

CWE-ID: CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer

Exploit availability: No


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary within the get_cert_name() function in gnutls.c. A remote attacker can trick the victim to connect to a malicious VPN server, trigger buffer overflow and crash the client or execute arbitrary code on the system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.


Install update from vendor's website.

Vulnerable software versions

OpenConnect VPN Client: 3.99, 4.00, 4.01, 4.02, 4.03, 4.04, 4.05, 4.06, 4.07, 4.08, 4.99, 5.00, 5.01, 5.02, 5.03, 5.99, 6.00, 7.00, 7.01, 7.02, 7.03, 7.04, 7.05, 7.06, 7.07, 7.08, 8.00, 8.01, 8.02, 8.03, 8.04, 8.05, 8.06, 8.07, 8.08, 8.09

CPE External links

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.