---
cve: "CVE-2021-22893"
severity: "CRITICAL"
cvss: 10.0
epss: "47.2%"
vendor: "n/a"
kev: true
exploited: true
published: "2021-04-23 16:29:43"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-10-21T11:37:12+02:00"
---

# CVE-2021-22893

> 10.0 CRITICAL · ⚠️ CISA KEV (1813 Tage) · 🔓 Exploited

## Beschreibung

Pulse Connect Secure 9.0R3/9.1R1 and higher is vulnerable to an authentication bypass vulnerability exposed by the Windows File Share Browser and Pulse Secure Collaboration features of Pulse Connect Secure that can allow an unauthenticated user to perform remote arbitrary code execution on the Pulse Connect Secure gateway. This vulnerability has been exploited in the wild.

## CNA-Record (Kanon, cvelistV5)

- CNA: **hackerone**
- State: PUBLISHED
- Stand: 2026-08-12 03:55:19

## CISA-Anreicherung (vulnrichment/ADP)

- CISA KEV seit: **03.11.2021**
- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **active**
  - Automatable: **yes**
  - Technical Impact: **total**

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Schwachstellen-Klasse

- **CWE-287** — Improper Authentication
  When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

## Angriffsmuster (CAPEC)

- [CAPEC-22 — Exploiting Trust in Client](https://capec.mitre.org/data/definitions/22.html) _(Severity: High)_
- [CAPEC-57 — Utilizing REST's Trust in the System Resource to Obtain Sensitive Data](https://capec.mitre.org/data/definitions/57.html) _(Severity: Very High)_
- [CAPEC-114 — Authentication Abuse](https://capec.mitre.org/data/definitions/114.html) _(Severity: Medium)_
- [CAPEC-115 — Authentication Bypass](https://capec.mitre.org/data/definitions/115.html) _(Severity: Medium)_
- [CAPEC-151 — Identity Spoofing](https://capec.mitre.org/data/definitions/151.html) _(Severity: Medium)_
- [CAPEC-194 — Fake the Source of Data](https://capec.mitre.org/data/definitions/194.html) _(Severity: Medium)_
- [CAPEC-593 — Session Hijacking](https://capec.mitre.org/data/definitions/593.html) _(Severity: Very High)_
- [CAPEC-633 — Token Impersonation](https://capec.mitre.org/data/definitions/633.html) _(Severity: Medium)_

## ATT&CK-Techniken

- [T1040 — Network Sniffing](https://attack.mitre.org/techniques/T1040/)
- [T1548 — Abuse Elevation Control Mechanism](https://attack.mitre.org/techniques/T1548/)
- [T1185 — Browser Session Hijacking](https://attack.mitre.org/techniques/T1185/)
- [T1550.001 — Use Alternate Authentication Material:Application Access Tok](https://attack.mitre.org/techniques/T1550/001/)
- [T1563 — Remote Service Session Hijacking](https://attack.mitre.org/techniques/T1563/)
- [T1134 — Access Token Manipulation](https://attack.mitre.org/techniques/T1134/)

## Referenzen

- <https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44784/>
- <https://blog.pulsesecure.net/pulse-connect-secure-security-update/>
- <https://www.fireeye.com/blog/threat-research/2021/04/suspected-apt-actors-leverage-bypass-techniques-pulse-secure-zero-day.html>
- <https://kb.cert.org/vuls/id/213092>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2021-22893/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_