CVE-2020-15104

TLS Validation Vulnerability in Envoy

MEDIUM
5.4
CVSS Score
Published: July 14, 2020 at 10:05 PM UTC
Updated: June 17, 2026 at 02:56 AM UTC
1 product affected across 1 vendorEnvoy

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.3%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.12.6v < 1.13.4v < 1.14.41.13.0 ≤ v < 1.13.41.14.0 ≤ v < 1.14.4
Affected range stops below 1.12.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.13.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.14.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-346

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