Denial of service in Go programming language

Published: 2021-08-09 | Updated: 2021-08-25

Risk	Medium
Patch available	YES
Number of vulnerabilities	1
CVE-ID	CVE-2021-34558
CWE-ID	CWE-295
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available.
Vulnerable software	Go programming language Universal components / Libraries / Scripting languages
Vendor	Google

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Improper Certificate Validation

EUVDB-ID: #VU55665

Risk: Medium

CVSSv4.0: 7.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2021-34558

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper certificate verification in crypto/tls package in Go when processing X.509 certificates. The application does not properly assert that the type of public key in an X.509 certificate matches the expected type when doing a RSA based key exchange, allowing a malicious TLS server to cause a TLS client to panic.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Go programming language: 1.16 - 1.16.5

CPE2.3

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.