What is CVE-2018-21246?

CVE-2018-21246 is a critical-severity vulnerability in Caddyserver Caddy, classified under Improper Authentication. CVSS score: 9.8/10. Published 2020-06-15.

How severe is CVE-2018-21246?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2018-21246 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Auth bypass in Caddyserver Caddy

CVE-2018-21246

Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.

Vulnerability class: Broken Authentication

EPSS: 0.027 (84.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Caddyserver Caddy
N/a — versions n/a

Weakness classification (CWE)

CWE-287 — Improper Authentication

Public proof-of-concept exploits

References

cve@mitre.org (Third Party Advisory, x_refsource_MISC, Release Notes)
cve@mitre.org (Third Party Advisory, x_refsource_MISC)

Frequently asked questions

What is CVE-2018-21246?: CVE-2018-21246 is a critical-severity vulnerability in Caddyserver Caddy, classified under Improper Authentication. CVSS score: 9.8/10. Published 2020-06-15.
How severe is CVE-2018-21246?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2018-21246 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.