Vulnerability identifier: #VU18254

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-3863

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
libssh2
Client/Desktop applications / Software for system administration

Vendor: libssh2.org

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing total length of multiple keyboard interactive response messages that exceeds the value of unsigned char max characters. A remote attacker can trick the victim to connect to a malicious SSH server, trigger our of bounds write and execute arbitrary code on the system with privileges of the user, running the affected application.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

libssh2: 1.0 - 1.8.0

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External links
http://www.libssh2.org/CVE-2019-3863.html

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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.