What is the CVSS score of CVE-2023-27487?

CVE-2023-27487 has a CVSS 3.1 base score of 9.1 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.6%.

Is there a public PoC exploit available for CVE-2023-27487?

Yes, a public proof-of-concept exploit is available for CVE-2023-27487. Prioritise patching immediately. EPSS: 0.6%.

Envoy CVE-2023-27487

CRITICAL

Improper Input Validation (CWE-20)

2023-04-04 security-advisories@github.com

Authentication Bypass Envoy

9.1

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.1 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

CVE Published

Apr 04, 2023 - 16:15 nvd

CRITICAL 9.1

DescriptionNVD

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, the client may bypass JSON Web Token (JWT) checks and forge fake original paths. The header x-envoy-original-path should be an internal header, but Envoy does not remove this header from the request at the beginning of request processing when it is sent from an untrusted client. The faked header would then be used for trace logs and grpc logs, as well as used in the URL used for jwt_authn checks if the jwt_authn filter is used, and any other upstream use of the x-envoy-original-path header. Attackers may forge a trusted x-envoy-original-path header. Versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9 have patches for this issue.

AnalysisAI

Envoy is an open source edge and service proxy designed for cloud-native applications. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified under CWE-20. 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, the client may bypass JSON Web Token (JWT) checks and forge fake original paths. The header x-envoy-original-path should be an internal header, but Envoy does not remove this header from the request at the beginning of request processing when it is sent from an untrusted client. The faked header would then be used for trace logs and grpc logs, as well as used in the URL used for jwt_authn checks if the jwt_authn filter is used, and any other upstream use of the x-envoy-original-path header. Attackers may forge a trusted x-envoy-original-path header. Versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9 have patches for this issue. Affected products include: Envoyproxy Envoy.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.