---
cve: "CVE-2021-31355"
severity: "HIGH"
cvss: 8.0
epss: "81%"
vendor: "Juniper Networks"
kev: false
exploited: false
published: "2021-10-19 19:15:08"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T01:49:38+02:00"
---

# CVE-2021-31355

> 8.0 HIGH

## Beschreibung

A persistent cross-site scripting (XSS) vulnerability in the captive portal graphical user interface of Juniper Networks Junos OS may allow a remote authenticated user to inject web script or HTML and steal sensitive data and credentials from a web administration session, possibly tricking a follow-on administrative user to perform administrative actions on the device. This issue affects Juniper Networks Junos OS: All versions, including the following supported releases: 12.3X48 versions prior to 12.3X48-D105; 15.1X49 versions prior to 15.1X49-D220; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R3-S3; 19.3 versions prior to 19.3R3-S4; 19.4 versions prior to 19.4R3-S6; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R1-S1, 20.2R2; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R2; 21.1 versions prior to 21.1R2.

## CVSS-Vektor

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

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

## Referenzen

- <https://kb.juniper.net/JSA11220>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-31355) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_