CVE-2019-20894
Improper Authentication
Traefik 2.x, in certain configurations, allows HTTPS sessions to proceed without mutual TLS verification in a situation where ERR_BAD_SSL_CLIENT_AUTH_CERT should have occurred.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
Traefik 2.x, in certain configurations, allows HTTPS sessions to proceed without mutual TLS verification in a situation where ERR_BAD_SSL_CLIENT_AUTH_CERT should have occurred.
- Record
CVE-2019-20894- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:P/I:N/A:N - Weakness
- CWE-295
- Updated
- 2026-11-02
CVE List No score
Traefik 2.x, in certain configurations, allows HTTPS sessions to proceed without mutual TLS verification in a situation where ERR_BAD_SSL_CLIENT_AUTH_CERT should have occurred.
- Record
CVE-2019-20894- Updated
- 2026-11-02
EUVDEUVD-2021-2101 No score
Traefik 2.x, in certain configurations, allows HTTPS sessions to proceed without mutual TLS verification in a situation where ERR_BAD_SSL_CLIENT_AUTH_CERT should have occurred.
- Record
EUVD-2021-2101- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-q9mp-79cp-9g8j
Improper Authentication
Traefik 2.x, in certain configurations, allows HTTPS sessions to proceed without mutual TLS verification in a situation where ERR_BAD_SSL_CLIENT_AUTH_CERT should have occurred.
- Record
GHSA-q9mp-79cp-9g8j- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-287, CWE-295
- Updated
- 2026-11-02
OSV
Traefik 2.x, in certain configurations, allows HTTPS sessions to proceed without mutual TLS verification in a situation where ERR_BAD_SSL_CLIENT_AUTH_CERT should have occurred.
- Record
CVE-2019-20894- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVGHSA-q9mp-79cp-9g8j
Improper Authentication
Traefik 2.x, in certain configurations, allows HTTPS sessions to proceed without mutual TLS verification in a situation where ERR_BAD_SSL_CLIENT_AUTH_CERT should have occurred.
- Record
GHSA-q9mp-79cp-9g8j- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-287, CWE-295
- Updated
- 2026-11-02
OSVGO-2022-0774 No score
Improper Authentication in github.com/containous/traefik
Improper Authentication in github.com/containous/traefik
- Record
GO-2022-0774- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/traefik/traefik/v2Go |
before 2.2.2 | 2.2.2 |
github.com/containous/traefikGo |
All versions | None known |
github.com/containous/traefik/v2Go |
before 2.2.2 | 2.2.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2019-20894 is a high vulnerability (CVSS 7.5) in Traefik, published July 2, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.56%, the 75th percentile. Fixed in github.com/traefik/traefik/v2 2.2.2.