Vulnerability Details : CVE-2021-36371
Potential exploit
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.)
Products affected by CVE-2021-36371
- cpe:2.3:a:getambassador:emissary-ingress:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-36371
0.07%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 18 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-36371
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
4.3
|
MEDIUM | AV:N/AC:M/Au:N/C:N/I:P/A:N |
8.6
|
2.9
|
NIST | |
|
3.7
|
LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
2.2
|
1.4
|
NIST |
CWE ids for CVE-2021-36371
-
The product does not validate, or incorrectly validates, a certificate.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-36371
-
https://github.com/emissary-ingress/emissary/issues/3340
Bypass mTLS by mixing SNI and Host headers · Issue #3340 · emissary-ingress/emissary · GitHubExploit;Third Party Advisory
-
https://github.com/emissary-ingress/emissary/releases/tag/v2.0.0-ea
Release Emissary Ingress 2.0.0-ea · emissary-ingress/emissary · GitHubRelease Notes;Third Party Advisory
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