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Case File

CVE-2021-20230

HIGH · CVSS 7.5 EPSS 1.18% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-02-23 · Last synced 2026-08-04

CyberRota Analysis

AI analysis pending.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links
github.com ↗

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2021-20230
Severity
HIGH
CVSS
7.5
EPSS
1.18%

Original NVD Description

A flaw was found in stunnel before 5.57, where it improperly validates client certificates when it is configured to use both redirect and verifyChain options. This flaw allows an attacker with a certificate signed by a Certificate Authority, which is not the one accepted by the stunnel server, to access the tunneled service instead of being redirected to the address specified in the redirect option. The highest threat from this vulnerability is to confidentiality.