Vulnerability in Envoyproxy Envoy
CVE-2022-21656
Envoy is an open source edge and service proxy, designed for cloud-native applications. The default_validator.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.
Vulnerability class: Improper Certificate Validation
EPSS: 0.007 (48.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Envoyproxy Envoy — versions < 1.20.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory, Issue Tracking)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2022-21656?
- CVE-2022-21656 is a high-severity vulnerability in Envoyproxy Envoy, classified under Improper Certificate Validation. CVSS score: 7.4/10. Published 2022-02-22.
- How severe is CVE-2022-21656?
- High severity. CVSS v3 base score is 7.4 out of 10.
- Is CVE-2022-21656 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.