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.

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Advisories
Source ID Title
EUVD EUVD EUVD-2021-1790 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.
Github GHSA Github GHSA GHSA-m697-4v8f-55qg Header dropping in traefik
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 24 Feb 2026 17:00:00 +0000

Type Values Removed Values Added
Title Drop Headers via Malicious Connection Header Drop Headers via Malicious Connection Header

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2024-08-03T23:33:55.883Z

Reserved: 2021-05-12T00:00:00.000Z

Link: CVE-2021-32813

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-08-03T23:15:07.370

Modified: 2024-11-21T06:07:48.107

Link: CVE-2021-32813

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses