traefik: Authentication Bypass Using an Alternate Path or Channel
CVE-2026-48020 is a critical-severity authentication bypass using an alternate path or channel vulnerability in traefik, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected traefik versions: >= 3.7.0-ea.1, < 3.7.3; >= 3.0.0-beta1, < 3.6.19; < 2.11.48. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.78% chance of exploitation within 30 days, higher than 56% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of traefik you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Traefik | traefik | >= 3.7.0-ea.1, < 3.7.3; >= 3.0.0-beta1, < 3.6.19; < 2.11.48 | Not stated |
| Red Hat | Red Hat OpenShift Dev Spaces 3.30 | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.8 | High | CNA (github.com) |
| CVSS 3.1 | 10.0 | Critical | NVD |
| CVSS 3.1 | 9.1 | Critical | CNA |
Official description
Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.48, 3.6.19, and 3.7.3, there is a high severity vulnerability in Traefik's StripPrefix middleware that allows an unauthenticated attacker to bypass route-level authentication and authorization. When a public router matches on a PathPrefix rule and applies the StripPrefix middleware, a request path containing .. or its percent-encoded form %2e%2e can match the public route at routing time and then, after the prefix is stripped and the path is normalized, resolve to a path served by a separate, authenticated router. As a result, an attacker can reach protected backend paths — such as admin or internal configuration endpoints — without satisfying the authentication middleware attached to the protected router. This vulnerability is fixed in 2.11.48, 3.6.19, and 3.7.3.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass Using an Alternate Path or Channel
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
How developers prevent this class of flaw
- Funnel all access through a single choke point to simplify how users can access a resource. For every access, perform a check to determine if the user has permissions to access the resource.
More Authentication Bypass Using an Alternate Path or Channel vulnerabilities (CWE-288)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/traefik/traefik/security/advisories/GHSA-xf64-8mw2-4gr2Exploit, Mitigation
Patches and release notes
- github.com/traefik/traefik/releases/tag/v2.11.48Release Notes
- github.com/traefik/traefik/releases/tag/v3.6.19Release Notes
- github.com/traefik/traefik/releases/tag/v3.7.3Release Notes
Other references
Other vulnerabilities in traefik
- 8.7 High severity
- 8.7 High severity
- 9.3 Critical severity
- 8.7 High severity
- 8.7 High severity
- 8.7 High severity
Recent Authentication Bypass Using an Alternate Path or Channel vulnerabilities
- 10.0 Critical severity
- 10.0 Critical severity
- 8.1 High severity
- 8.2 High severity
- 8.1 High severity
- 8.7 High severity
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