---
title: "CVE-2026-88877: Traefik - Authentication Bypass & Broken Access Control"
description: "Traefik v3.7.0 to v3.7.11 contains a broken access control vulnerability caused by mishandling of Kubernetes ingress-nginx annotations, letting attackers bypass authentication and other middlewares, exploit requires crafted Host header with non-numeric or empty port."
url: https://panop.io/threat-heartbeat/CVE-2026-88877/
---

# CVE-2026-88877 Traefik - Authentication Bypass & Broken Access Control

Traefik v3.7.0 to v3.7.11 contains a broken access control vulnerability caused by mishandling of Kubernetes ingress-nginx annotations, letting attackers bypass authentication and other middlewares, exploit requires crafted Host header with non-numeric or empty port.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

Proof of concept available

Authentication

Not required

EPSS

0.65% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-88877)

## Details

Type

Authentication Bypass

Impact

Broken Access Control, Information Disclosure

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

10 September 2026

Updated

15 October 2026

Weakness

[CWE-639](https://cwe.mitre.org/data/definitions/639.html)

## Vendor fix

Upgrade to version 3.7.12 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-88877](https://nvd.nist.gov/vuln/detail/CVE-2026-88877)
- [https://www.vulncheck.com/advisories/traefik-3.7.0-authentication-bypass-via-from-to-www-redirect](https://www.vulncheck.com/advisories/traefik-3.7.0-authentication-bypass-via-from-to-www-redirect)
- [https://github.com/traefik/traefik/security/advisories/GHSA-cjr6-pf59-jq29](https://github.com/traefik/traefik/security/advisories/GHSA-cjr6-pf59-jq29)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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