// For flags

CVE-2023-27493

Envoy doesn't escape HTTP header values

Severity Score

9.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, Envoy does not sanitize or escape request properties when generating request headers. This can lead to characters that are illegal in header values to be sent to the upstream service. In the worst case, it can cause upstream service to interpret the original request as two pipelined requests, possibly bypassing the intent of Envoy’s security policy. Versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9 contain a patch. As a workaround, disable adding request headers based on the downstream request properties, such as downstream certificate properties.

A flaw was found in Envoy. Envoy doesn't escape HTTP header values due to a specifically constructed HTTP request or mTLS connection with a specifically crafted client certificate. Envoy configuration must also include an option to add request headers that were generated using inputs from the request, for example, the peer certificate SAN.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2023-03-01 CVE Reserved
  • 2023-04-04 CVE Published
  • 2024-08-02 CVE Updated
  • 2024-08-02 First Exploit
  • 2024-10-25 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-20: Improper Input Validation
  • CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Envoyproxy
Search vendor "Envoyproxy"
 Envoy
Search vendor "Envoyproxy" for product "Envoy"
 < 1.22.9
Search vendor "Envoyproxy" for product "Envoy" and version " < 1.22.9"
-
Affected
Envoyproxy
Search vendor "Envoyproxy"
 Envoy
Search vendor "Envoyproxy" for product "Envoy"
 >= 1.23.0 < 1.23.6
Search vendor "Envoyproxy" for product "Envoy" and version " >= 1.23.0 < 1.23.6"
-
Affected
Envoyproxy
Search vendor "Envoyproxy"
 Envoy
Search vendor "Envoyproxy" for product "Envoy"
 >= 1.24.0 < 1.24.4
Search vendor "Envoyproxy" for product "Envoy" and version " >= 1.24.0 < 1.24.4"
-
Affected
Envoyproxy
Search vendor "Envoyproxy"
 Envoy
Search vendor "Envoyproxy" for product "Envoy"
 >= 1.25.0 < 1.25.3
Search vendor "Envoyproxy" for product "Envoy" and version " >= 1.25.0 < 1.25.3"
-
Affected