Vulnerability identifier: #VU51441

Vulnerability risk: Low

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-2021-20231

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

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

Vendor: GnuTLS

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error in client sending key_share extension. A remote attacker can trick the victim to connect to a malicious server using a large Client Hello message over TLS 1.3, trigger a use-after-free error and crash the application or execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

GnuTLS: 3.6.0 - 3.7.0

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External links
http://bugzilla.redhat.com/show_bug.cgi?id=1922276
http://www.gnutls.org/security-new.html#GNUTLS-SA-2021-03-10

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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.