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Fencer Vulns
high 7.5

CVE-2019-20894 json

Improper Authentication

published 2020-07-02 6 y ago modified 2026-06-17 4 mo ago also GHSA-q9mp-79cp-9g8j , GO-2022-0774 , EUVD-2021-2101

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 75%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/traefik/traefik/v2 2.2.2
  • go github.com/containous/traefik/v2 2.2.2
  • traefik traefik 2.0.1

Exploit prediction

1.56% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/containous/traefik/issues/5312 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/traefik/traefik/v2
<2.2.2
2.2.2
go github.com/containous/traefik
all versions
 no fix listed
go github.com/containous/traefik/v2
<2.2.2
2.2.2

Classification

Weakness
  • CWE-295 Improper Certificate Validation
  • CWE-287 Improper Authentication

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.