Vulnerability Report

CVE-2021-32780

Title: Envoy Abnormal Termination due to H/2 connection state transition

Denial of Service

Proof Of Concept

No public PoC currently indexed for CVE-2021-32780.

CWE Category CWE-754
Published Date Aug 24, 2021
Modified Date Nov 21, 2024
Exploit Status Not Found
Score 8.6 CVSS v3.1
Exploit Probability (EPSS)
1.23%

Vulnerability Summary

CVE-2021-32780: Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions Envoy transitions a H/2 connection to the CLOSED state when it receives a GOAWAY frame without any streams outstanding. The connection state is transitioned to DRAINING when it receives a SETTING frame with the SETTINGS_MAX_CONCURRENT_STREAMS parameter set to 0. Receiving these two frames in the same I/O event results in abnormal termination of the Envoy process due to invalid state transition from CLOSED to DRAINING. A sequence of H/2 frames delivered by an untrusted upstream server will result in Denial of Service in the presence of untrusted **upstream** servers. Envoy versions 1.19.1, 1.18.4 contain fixes to stop processing of pending H/2 frames after connection transition to the CLOSED state.

Impacted Vendors

E
envoyproxy 1
E
enphase 1

Reference Links

https://github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8 https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history https://github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8 https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history
CVSS v3.1
Source Entity [email protected]
Severity HIGH
8.6
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
5.0
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:L/Au:N/C:N/I:N/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-32780 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected Stack

No specific products linked.