CVE-2021-34558

MEDIUM

GO < 1.15.14 - Improper Certificate Validation

Title source: rule
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-34558. PoCs published by alexzorin.

AI-analyzed exploit summary This repository contains a functional proof-of-concept exploit for CVE-2021-34558, a TLS handshake vulnerability in Go's crypto/tls package. The exploit demonstrates a panic caused by a type mismatch between ECDSA and RSA keys during the TLS handshake process.

Description

The crypto/tls package of Go through 1.16.5 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.

Exploits (1)

nomisec WORKING POC 46 stars
by alexzorin · poc
https://github.com/alexzorin/cve-2021-34558

This repository contains a functional proof-of-concept exploit for CVE-2021-34558, a TLS handshake vulnerability in Go's crypto/tls package. The exploit demonstrates a panic caused by a type mismatch between ECDSA and RSA keys during the TLS handshake process.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Go crypto/tls package (versions before 1.16.6)
No auth needed
Prerequisites: Go environment · Network access to target server
devstral-2 · analyzed Feb 18, 2026 Full analysis →

References (16)

Core 16
Core References
Mailing List, Third Party Advisory x_refsource_misc
https://groups.google.com/g/golang-announce
Release Notes, Vendor Advisory x_refsource_misc
https://golang.org/doc/devel/release#go1.16.minor
Patch, Third Party Advisory x_refsource_misc
https://www.oracle.com/security-alerts/cpuoct2021.html
Mailing List, Release Notes, Third Party Advisory x_refsource_misc
https://groups.google.com/g/golang-announce/c/n9FxMelZGAQ
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20210813-0005/
Patch, Third Party Advisory x_refsource_misc
https://www.oracle.com/security-alerts/cpujan2022.html
Third Party Advisory vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/202208-02

Scores

CVSS v3 6.5
EPSS 0.0703
EPSS Percentile 93.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Details

CWE
CWE-295
Status published
Products (7)
fedoraproject/fedora 33
fedoraproject/fedora 34
golang/go < 1.15.14
netapp/cloud_insights_telegraf
netapp/storagegrid
netapp/trident
oracle/timesten_in-memory_database < 21.1.1.1.0
Published Jul 15, 2021
Tracked Since Feb 18, 2026