# CVE-2026-85595: Traefik digestAuth authentication bypass

Source: https://junglewise.ai/threats/cve-2026-85595-traefik-digestauth-authentication-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-04. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-85595 · Severity: critical · CVSS 9.8 · Published 2026-09-04

Traefik is a reverse proxy and load balancer widely used to route incoming traffic and enforce authentication policies. The digestAuth middleware—designed to verify user credentials—contains a critical flaw that allows attackers to completely bypass authentication without knowing any valid username or password. An unauthenticated attacker can make two simple HTTP requests to access any protected service, including the Traefik dashboard and admin APIs, compromising confidentiality and integrity of protected resources.

Technologies: [Traefik](https://junglewise.ai/threats/technologies/traefik). Vendors: [Traefik](https://junglewise.ai/threats/vendors/traefik).

## Quick answers

**Is CVE-2026-85595 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-85595 being exploited in the wild.

**How severe is CVE-2026-85595?** Critical severity, with a CVSS score of 9.8, published 4 September 2026.

**Which products and versions are affected?** Traefik before v2.11.55 and v3.0.0 through v3.7.10.

**Is there a fix for CVE-2026-85595?** A patch was published on 2026-09-04: v2.11.55 and v3.7.11 released with patches Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-85595 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-85595?** Check whether you run Traefik at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a cryptographic authentication bypass in the digestAuth middleware caused by improper secret handling (CWE-287). When a user is not found in the configured user list, the secretDigest function returns an empty string instead of signalling an error. The underlying go-http-auth library then uses this empty string as the HA1 hash value and proceeds with HTTP Digest validation. Since the attacker controls the username, nonce, cnonce, nc, qop, method, and URI parameters (or receives the nonce from the server), they can compute a valid digest response offline: MD5("" + ":" + nonce + ":" + ...). The middleware then accepts any non-empty username returned by the library, allowing arbitrary authentication bypass with no preconditions. Patches are available in v2.11.55 and v3.7.11.

## Affected products

- Traefik Traefik before v2.11.55 and v3.0.0 through v3.7.10

## Timeline

- 2026-08-21: disclosed: GitHub Security Advisory GHSA-5w68-77r2-r64c published
- 2026-09-04: patched: v2.11.55 and v3.7.11 released with patches

## References

- [https://github.com/traefik/traefik/security/advisories/GHSA-5w68-77r2-r64c](https://github.com/traefik/traefik/security/advisories/GHSA-5w68-77r2-r64c)
- [https://www.vulncheck.com/advisories/traefik-before-2.11.55-authentication-bypass-via-digestauth](https://www.vulncheck.com/advisories/traefik-before-2.11.55-authentication-bypass-via-digestauth)

## Related threats

- [Traefik ForwardAuth connection pool identity leak via NTLM/Negotiate](https://junglewise.ai/threats/cve-2026-121966-traefik-2-x-before-2-11-60-and-3-x-before-3-7-16-sends)
- [Traefik FastProxy data race in HTTP/1 upgrades](https://junglewise.ai/threats/cve-2026-119574-traefik-from-3-2-0-before-3-7-15-contains-a-data-race-in-the)
- [Traefik authentication bypass in TLS options resolution](https://junglewise.ai/threats/cve-2026-114656-traefik-before-2-11-58-and-3-7-13-contains-an-authentication)
- [Traefik NTLM/Kerberos TLS configuration bypass](https://junglewise.ai/threats/cve-2026-114642-traefik-2-11-0-before-2-11-58-and-3-0-0-before-3-7-14-stores-its)
- [Traefik authentication bypass in backend connection pool](https://junglewise.ai/threats/cve-2026-114639-traefik-2-11-0-before-2-11-58-and-3-0-0-before-3-7-14-contains)