Vulnerability in Getambassador Emissary-Ingress
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 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.)
Vulnerability class: Improper Certificate Validation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.007 (52.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/emissary-ingress/emissary/issues/3340 (Exploit, Third Party Advisory)
- github.com/emissary-ingress/emissary/releases/tag/v2.0.0-ea (Third Party Advisory, Release Notes)
Frequently asked questions
- What is CVE-2021-36371?
- CVE-2021-36371 is a low-severity vulnerability in Getambassador Emissary-Ingress, classified under Improper Certificate Validation. CVSS score: 3.7/10. Published 2021-07-09.
- How severe is CVE-2021-36371?
- Low severity. CVSS v3 base score is 3.7 out of 10.