CVE-2026-71326
Low
Description
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.
SeverityLow
CVSS3.8
Exploit probability—
Product
Traefik
PublishedAug 6, 2026
First seenAug 6, 2026
Weakness typeCWE-287Improper authentication
How to fix
Update
- traefik traefik3.6.25, 3.7.10 or later
- github.com/traefik/traefik/v33.6.25, 3.7.10 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| traefik traefik | 3.6.11 ≤ v < 3.6.25, 3.7.0 ≤ v < 3.7.10 | 3.6.25, 3.7.10 |
| github.com/traefik/traefik/v3Go | 3.6.11 ≤ v < 3.6.25, 3.7.0 ≤ v < 3.7.10 | 3.6.25, 3.7.10 |
| github.com/traefik/traefikGo | No range specified | — |
| github.com/traefik/traefik/v2Go | No range specified | — |
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