CVE-2022-21656: X.509 subjectAltName matching bypass in Envoy
Envoy is an open source edge and service proxy, designed for cloud-native applications. The defaultvalidator.cc implementation used to implement the default certificate validation routines has a "type confusion" bug when processing subjectAltNames. This processing allows, for example, an rfc822Name or uniformResourceIndicator to be authenticated as a domain name. This confusion allows for the bypassing of nameConstraints, as processed by the underlying OpenSSL/BoringSSL implementation, exposing the possibility of impersonation of arbitrary servers. As a result Envoy will trust upstream certificates that should not be trusted.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is CVE-2022-21656?
CVE-2022-21656 is a vulnerability in the default_validator.cc implementation used by Envoy, which allows a type confusion bug when processing subjectAltNames.
What is the severity of CVE-2022-21656?
CVE-2022-21656 has a severity rating of high, with a CVSSv3 score of 5.9.
How does CVE-2022-21656 affect Envoy?
CVE-2022-21656 affects Envoy versions up to and including 1.20.2.
What is the CWE ID for CVE-2022-21656?
CVE-2022-21656 is associated with CWE-843 and CWE-295.
How can I fix CVE-2022-21656 in Envoy?
To fix CVE-2022-21656 in Envoy, update to a version that includes the fix, such as version 1.21.0 or later.