CVE-2020-15104

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account, but needs a user to act. Limited direct impact.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-07-14 22:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 02:56 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 4.6 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-07-14 22:15 UTC

Last modified

2026-06-17 02:56 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-346

Record status

Modified

Affected

• Envoyproxy Envoy < 1.12.6
• Envoyproxy Envoy < 1.13.4
• Envoyproxy Envoy < 1.14.4

Attack profile CVSS 3.1 · 4.6

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2020-15104.md and follow it. Check whether this project is affected by CVE-2020-15104. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

Copy as ticket · More options · Status badge