// For flags

CVE-2021-31920

istio/istio: HTTP request with escaped slash characters can bypass authorization mechanisms

Severity Score

6.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Istio before 1.8.6 and 1.9.x before 1.9.5 has a remotely exploitable vulnerability where an HTTP request path with multiple slashes or escaped slash characters (%2F or %5C) could potentially bypass an Istio authorization policy when path based authorization rules are used.

Istio versiones anteriores a 1.8.6 y versiones 1.9.x anteriores a 1.9.5 presenta una vulnerabilidad explotable de forma remota en la que una ruta de petición HTTP con múltiples barras o caracteres de barra de escape (%2F o %5C) podría omitir potencialmente una política de autorización de Istio cuando las reglas de autorización basadas en la ruta son usadas

An authorization bypass flaw was found in Istio. This flaw allows an attacker to craft an HTTP request that defines a certain pattern of escaped characters in the URI path (such as %2F, %2f, %5C, or %5c), allowing them to bypass the authorization service. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
Low
Authentication
Single
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-04-30 CVE Reserved
  • 2021-05-12 CVE Published
  • 2024-08-03 CVE Updated
  • 2024-08-03 First Exploit
  • 2024-09-29 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
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"
 < 1.8.6
Search vendor "Istio" for product "Istio" and version " < 1.8.6"
-
Affected
Istio
Search vendor "Istio"
 Istio
Search vendor "Istio" for product "Istio"
 >= 1.9.0 < 1.9.5
Search vendor "Istio" for product "Istio" and version " >= 1.9.0 < 1.9.5"
-
Affected