Use-after-free in gnutls

Published: 2021-03-14

Risk	Low
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2021-20232 CVE-2021-20231
CWE-ID	CWE-416
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	GnuTLS Universal components / Libraries / Libraries used by multiple products
Vendor	GnuTLS

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Use-after-free

EUVDB-ID: #VU51442

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-2021-20232

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error in client_send_params in lib/ext/pre_shared_key.c. 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

External links

http://bugzilla.redhat.com/show_bug.cgi?id=1922275
http://www.gnutls.org/security-new.html#GNUTLS-SA-2021-03-10
http://gitlab.com/gnutls/gnutls/-/issues/1151

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.

2) Use-after-free

EUVDB-ID: #VU51441