---
cve: "CVE-2021-39156"
severity: "HIGH"
cvss: 8.1
epss: "1.1%"
vendor: "istio"
kev: false
exploited: false
published: "2021-08-24 22:30:12"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T05:43:51+02:00"
---

# CVE-2021-39156

> 8.1 HIGH · 🧪 PoC

## Beschreibung

Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies. Patches are available in Istio 1.11.1, Istio 1.10.4 and Istio 1.9.8. As a work around a Lua filter may be written to normalize the path.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 5336ff0f12bc093b728dac3a729b4b2bcbc3df65 (Commit)
- 61313778e0b785e401c696f5e92f47af069f96d0 (Commit)

## Referenzen

- <https://github.com/istio/istio/security/advisories/GHSA-hqxw-mm44-gc4r>
- <https://istio.io/latest/news/security/istio-security-2021-008>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-39156) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_