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GHSA-m697-4v8f-55qg

MediumCVSS 4.8 / 10
Published Aug 5, 2021·Last modified Mar 13, 2026
Affected Components(0)

No affected components available

Description

Impact

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.

Details

If you have a chain of Traefik middlewares, and one of them sets a request header Important-Security-Header, then sending a request with the following Connection header will cause it to be removed before the request was sent:

curl 'https://example.com' -H "Connection: Important-Security-Header" -0

In this case, the backend does not see the request header Important-Security-Header.

Patches

Traefik v2.4.x: https://github.com/traefik/traefik/releases/tag/v2.4.13

Workarounds

No.

For more information

If you have any questions or comments about this advisory, open an issue.

Risk Scores
Base Score
4.8

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data.

Threat Intelligence
4.4

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
1.10%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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