Vulnerability · Published Feb 22, 2022 · Assigned by GitHub_M

CVE-2022-21656X.509 subjectAltName matching bypass in Envoy

High 7.4

In plain English

A high-severity improper certificate validation in envoy from envoyproxy. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).

Severity (CVSS 3.1)7.4High

Exploit odds (30 days)0.7%top 47.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
envoyproxy	envoy	< 1.20.2

Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

https://github.com/envoyproxy/envoy/security/advisories/GHSA-c9g7-xwcv-pjx2 x_refsource_CONFIRM
https://github.com/envoyproxy/envoy/commit/bb95af848c939cfe5b5ee33c5b1770558077e64e x_refsource_MISC