# CVE-2023-47106: Incorrect processing of fragment in the URL leads to Authorization Bypass in Traefik

> Traefik incorrectly forwards URL fragments, allowing attackers to bypass frontend proxy access controls when used with another proxy like Nginx.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Dec 2023
- **Updated:** 2 Aug 2024
- **Also known as:** ECHO-3ccf-9fb8-6ebf, GHSA-fvhj-4qfh-q2hm, GO-2023-2376

## What is CVE-2023-47106?

CVE-2023-47106 is a medium-severity authentication bypass vulnerability in Traefik Traefik, published on 4 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Traefik is an open source HTTP reverse proxy and load balancer. When a request is sent to Traefik with a URL fragment, Traefik automatically URL encodes and forwards the fragment to the backend server. This violates RFC 7230 because in the origin-form the URL should only contain the absolute path and the query. When this is combined with another frontend proxy like Nginx, it can be used to bypass frontend proxy URI-based access control restrictions. This vulnerability has been addressed in versions 2.10.6 and 3.0.0-beta5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2023-47106?

7 open source packages ship an affected version, including github.com/traefik/traefik/v2, github.com/traefik/traefik and github.com/traefik/traefik/v3. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.10.6 |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.10.6 |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.10.6 |
| `github.com/traefik/traefik` | Go | All versions | None |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.0.0-beta5 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.0.0-beta5 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.0.0-beta5 |

Products: Traefik Traefik.

## How do I fix CVE-2023-47106?

Upgrade github.com/traefik/traefik/v2 to 2.10.6 or later.

## Is CVE-2023-47106 being exploited?

There is no known exploitation of CVE-2023-47106 in the wild and no public exploit code.

## Other vulnerabilities in Traefik Traefik

- [CVE-2024-45410](https://insights.sbomify.com/CVE-2024-45410/): HTTP client can remove the X-Forwarded headers in Traefik (critical 9.8)
- [CVE-2026-88877](https://insights.sbomify.com/CVE-2026-88877/): Traefik v3.7.0 Authentication Bypass via from-to-www-redirect (critical 9.3)
- [CVE-2026-85595](https://insights.sbomify.com/CVE-2026-85595/): Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth (critical 9.3)
- [CVE-2026-88007](https://insights.sbomify.com/CVE-2026-88007/): Traefik HTTP/3 Backend NTLM Connection Reuse (critical 9.1)
- [CVE-2026-88009](https://insights.sbomify.com/CVE-2026-88009/): Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-47106 and fix it if it is affected.

What it is: CVE-2023-47106 is a medium-severity authentication bypass vulnerability in Traefik Traefik, published on 4 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-47106 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.10.6
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.10.6
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.10.6
- github.com/traefik/traefik (Go): affected all versions; no fix listed
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.0.0-beta5
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.0.0-beta5
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.0.0-beta5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-47106/ (Markdown: https://insights.sbomify.com/CVE-2023-47106/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-47106
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-47106
- OSV: https://osv.dev/vulnerability/CVE-2023-47106

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-47106/
Summaries are generated and may contain mistakes; the official description above is the record.