CVE-2020-15104

Description

In Envoy before versions 1.12.6, 1.13.4, 1.14.4, and 1.15.0 when validating TLS certificates, Envoy would incorrectly allow a wildcard DNS Subject Alternative Name apply to multiple subdomains. For example, with a SAN of *.example.com, Envoy would incorrectly allow nested.subdomain.example.com, when it should only allow subdomain.example.com. This defect applies to both validating a client TLS certificate in mTLS, and validating a server TLS certificate for upstream connections. This vulnerability is only applicable to situations where an untrusted entity can obtain a signed wildcard TLS certificate for a domain of which you only intend to trust a subdomain of. For example, if you intend to trust api.mysubdomain.example.com, and an untrusted actor can obtain a signed TLS certificate for *.example.com or *.com. Configurations are vulnerable if they use verify_subject_alt_name in any Envoy version, or if they use match_subject_alt_names in version 1.14 or later. This issue has been fixed in Envoy versions 1.12.6, 1.13.4, 1.14.4, 1.15.0.

How to fix CVE-2020-15104

To remediate CVE-2020-15104, upgrade the affected package to a fixed version below.

• —upgrade to 1.12.6 or later

Is CVE-2020-15104 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• from 0, < 1.12.6, >= 1.13.0, < 1.13.4, >= 1.14.0, < 1.14.4

CVSS scores

References (2)

• WEBgithub.com/envoyproxy/envoy/security/advisories/GHSA-w5f5-6qhq-hhrg
• WEBnvd.nist.gov/vuln/detail/CVE-2020-15104