// For flags

CVE-2021-39156

Fragments in Path May Lead to Authorization Policy Bypass

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

Istio es una plataforma de código abierto que proporciona una forma uniforme de integrar microservicios, administrar el flujo de tráfico entre microservicios, aplicar políticas y agregar datos de telemetría. Istio versiones 1.11.0, 1.10.3 y por debajo, y versiones 1.9.7 y por debajo, contienen una vulnerabilidad explotable de forma remota en la que una petición HTTP con el parámetro "#fragment" en la ruta puede omitir las políticas de autorización basadas en la ruta URI de Istio. Los parches están disponibles en Istio versión 1.11.1, Istio versión 1.10.4 e Istio versión 1.9.8. Como solución, puede escribirse un filtro Lua para normalizar la ruta.

An authorization bypass vulnerability was found in istio/istio. An HTTP request is incorrectly evaluated when a URI #fragment is specified. This flaw allows an attacker to bypass an Istio URI-based authorization rule. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-08-16 CVE Reserved
  • 2021-08-24 CVE Published
  • 2024-05-09 EPSS Updated
  • 2024-08-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-706: Use of Incorrectly-Resolved Name or Reference
  • CWE-863: Incorrect Authorization
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Istio
Search vendor "Istio"
 Istio
Search vendor "Istio" for product "Istio"
 < 1.9.8
Search vendor "Istio" for product "Istio" and version " < 1.9.8"
-
Affected
Istio
Search vendor "Istio"
 Istio
Search vendor "Istio" for product "Istio"
 >= 1.10.0 < 1.10.3
Search vendor "Istio" for product "Istio" and version " >= 1.10.0 < 1.10.3"
-
Affected
Istio
Search vendor "Istio"
 Istio
Search vendor "Istio" for product "Istio"
 >= 1.11.0 < 1.11.1
Search vendor "Istio" for product "Istio" and version " >= 1.11.0 < 1.11.1"
-
Affected