Vulnerability Description
Emissary-Ingress (formerly Ambassador API Gateway) through 1.13.9 allows attackers to bypass client certificate requirements (i.e., mTLS cert_required) on backend upstreams when more than one TLSContext is defined and at least one configuration exists that does not require client certificate authentication. The attacker must send an SNI specifying an unprotected backend and an HTTP Host header specifying a protected backend. (2.x versions are unaffected. 1.x versions are unaffected with certain configuration settings involving prune_unreachable_routes and a wildcard Host resource.)
CVSS Score
LOW
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Getambassador | Emissary-Ingress | <= 1.13.9 |
Related Weaknesses (CWE)
References
- https://github.com/emissary-ingress/emissary/issues/3340ExploitThird Party Advisory
- https://github.com/emissary-ingress/emissary/releases/tag/v2.0.0-eaRelease NotesThird Party Advisory
- https://github.com/emissary-ingress/emissary/issues/3340ExploitThird Party Advisory
- https://github.com/emissary-ingress/emissary/releases/tag/v2.0.0-eaRelease NotesThird Party Advisory
FAQ
What is CVE-2021-36371?
CVE-2021-36371 is a vulnerability with a CVSS score of 3.7 (LOW). Emissary-Ingress (formerly Ambassador API Gateway) through 1.13.9 allows attackers to bypass client certificate requirements (i.e., mTLS cert_required) on backend upstreams when more than one TLSConte...
How severe is CVE-2021-36371?
CVE-2021-36371 has been rated LOW with a CVSS base score of 3.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-36371?
Check the references section above for vendor advisories and patch information. Affected products include: Getambassador Emissary-Ingress.