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TI-2021-12478 Aliases CVE-2021-32813GHSA-m697-4v8f-55qg

Drop Headers via Malicious Connection Header

Priority LOW 37CWE-913Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

EPSS 0.011 65th percentileScored 2026-11-07
Fix Fixed traefik (traefik): 2.4.13github.com/traefik/traefik/v2 (Go): 2.4.13

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
traefiktraefikbefore 2.4.13; up to 1.7.302.4.13Patch availableCNA
—github.com/traefik/traefik/v2 (Go)before 2.4.132.4.13Patch availableGHSA-m697-4v8f-55qg
—github.com/traefik/traefik (Go)up to 1.7.30—No fix listedGHSA-m697-4v8f-55qg
  • traefik Vendortraefik Affected before 2.4.13; up to 1.7.30 Fixed in 2.4.13 Patch available CNA
  • github.com/traefik/traefik/v2 (Go) Vendor— Affected before 2.4.13 Fixed in 2.4.13 Patch available GHSA-m697-4v8f-55qg
  • github.com/traefik/traefik (Go) Vendor— Affected up to 1.7.30 Fixed in — No fix listed GHSA-m697-4v8f-55qg

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*before 2.4.13Vulnerabletraefik
  • cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* Versions before 2.4.13 Vulnerable ·traefik

Remediation

  • Fix · CNA traefik (traefik) Fixed in 2.4.13
  • Fix · GHSA-m697-4v8f-55qg github.com/traefik/traefik/v2 (Go) Fixed in 2.4.13 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-32813
  2. 2026-10-03 Alias added: GHSA-m697-4v8f-55qg

References

Patch 1

Advisory 3

  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2023-25774 Uncontrolled Resource Consumption in Traefik CVSS 3.1HIGH 7.5
  • TI-2025-40914 Traefik doesn't Prevent Path Normalization Bypass in Router + Middleware Rules CVSS 4.0MEDIUM 6.9
  • TI-2022-07529 Authorization header displayed in the debug logs CVSS 3.1MEDIUM 6.5
  • TI-2024-30459 HTTP client can remove the X-Forwarded headers in Traefik CVSS 3.1CRITICAL 9.8
  • TI-2026-60261 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect CVSS 4.0CRITICAL 9.3
See all 83 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences