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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.007 (50.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
- Envoyproxy Envoy — versions < 1.20.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/envoyproxy/envoy/security/advisories/GHSA-c9g7-xwcv-pjx2 (Third Party Advisory, Issue Tracking)
- github.com/envoyproxy/envoy/commit/bb95af848c939cfe5b5ee33c5b1770558077e64e (Patch, Third Party Advisory)
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.