Vulnerability identifier: #VU56217

Vulnerability risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-3634

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
libssh
Universal components / Libraries / Libraries used by multiple products

Vendor: libssh

Description

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

The vulnerability exists due to a boundary error when handling shared secrets. A remote attacker can supply a shared secret of a different size, trigger a memory corruption during the second key re-exchange and crash the application or potentially execute arbitrary code.

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

Mitigation
Install updates from vendor's website.

Vulnerable software versions

libssh: 0.9.0 - 0.9.5

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External links
http://bugzilla.redhat.com/show_bug.cgi?id=1978810

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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.