CVE-2021-36371
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…
Does this matter?
Lower severity and a low EPSS score (0.74%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 3.7 LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- EPSS
- 0.74% probability · 53th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-295
- Affected
- getambassador/emissary-ingress
- Source
- cve@mitre.org
References
- https://github.com/emissary-ingress/emissary/issues/3340Exploit, Third Party Advisory
- https://github.com/emissary-ingress/emissary/releases/tag/v2.0.0-eaRelease Notes, Third Party Advisory
- https://github.com/emissary-ingress/emissary/issues/3340Exploit, Third Party Advisory
- https://github.com/emissary-ingress/emissary/releases/tag/v2.0.0-eaRelease Notes, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.