Vulnerability in Traefik

CVE-2021-32813

Traefik is an HTTP reverse proxy and load balancer. Prior to version 2.4.13, there exists a potential header vulnerability in Traefik's handling of the Connection header. Active exploitation of this issue is unlikely, as it requires that a removed header would lead to a privilege escalation, however, the Traefik team has addressed this issue to prevent any potential abuse. If one has a chain of Traefik middlewares, and one of them sets a request header, then sending a request with a certain Connection header will cause it to be removed before the request is sent. In this case, the backend does not see the request header. A patch is available in version 2.4.13. There are no known workarounds aside from upgrading.

EPSS: 0.011 (62.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

  • Traefik — versions < 2.4.13, <= 1.7.30

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-32813?
CVE-2021-32813 is a medium-severity vulnerability in Traefik, classified under Improper Control of Dynamically-Managed Code Resources. CVSS score: 4.8/10. Published 2021-08-03.
How severe is CVE-2021-32813?
Medium severity. CVSS v3 base score is 4.8 out of 10.