CVE-2026-71326

What it is

Traefik is an open source HTTP reverse proxy and load balancer. From 3.6.11 until 3.6.25 and 3.7.10, Traefik's BasicAuth middleware in pkg/middlewares/auth/basic_auth.go deduplicates concurrent password checks with a singleflight key built from the delimiter-free concatenation of password and secret, allowing an attacker who has a valid credential and the stored hash to authenticate as an unconfigured username when headerField trusts the forwarded identity. This issue is fixed in 3.6.25 and 3.7.10.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. Limited direct impact.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-08-06 22:18 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-16 20:44 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 2.1 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-08-06 22:18 UTC

Last modified

2026-09-16 20:44 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-287 · Improper authentication

Record status

Analyzed

Affected

• Traefik < 3.6.25
• Traefik < 3.7.10

Attack profile CVSS 4.0 · 2.1

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

High

User interaction

None

Confidentiality

Low

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-71326.md and follow it. Check whether this project is affected by CVE-2026-71326. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

Copy as ticket · More options · Status badge