# CVE-2026-65600: Traefik before v2.11.52 Authentication Bypass via ReplacePathRegex

> Unauthenticated attackers can bypass authentication in Traefik by exploiting path traversal in ReplacePathRegex middleware when configured with vulnerable regex patterns.

- **Severity:** High 7.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Jul 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-cxjq-mrr5-89rv, GO-2026-6208, MINI-jwcx-pw4m-vmqw, MINI-pj68-g4wh-x586, MINI-xxgx-5x88-crp2

## What is CVE-2026-65600?

CVE-2026-65600 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 22 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-controlled path segments without a mandatory path separator (e.g. regex "^/api(.*)", replacement "/$1"), the middleware forwards the replaced path to the backend without validating that it matches its normalized form. An unauthenticated remote attacker can send a crafted request (e.g. GET /api../admin) that produces an un-normalized path such as /../admin, which a backend that normalizes paths resolves to a protected route, bypassing authentication middleware. Fixed in v2.11.52, v3.6.23, and v3.7.7.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-65600?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.23, 3.7.7 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.23 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.23 |
| `github.com/traefik/traefik/v3` | Go | From 3.7.0 | 3.7.7 |
| `github.com/traefik/traefik/v3` | Go | From 3.7.0 | 3.7.7 |
| `github.com/traefik/traefik` | Go | All versions | None |
| `github.com/traefik/traefik` | Go | All versions to 1.7.34 | None |
| `github.com/traefik/traefik` | Go | All versions to 1.7.34 | None |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.11.52 |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.11.52 |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.11.52 |

Products: Traefik Traefik.

## How do I fix CVE-2026-65600?

Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.23 or 3.7.7.

## Is CVE-2026-65600 being exploited?

There is no known exploitation of CVE-2026-65600 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-2026-65600 and fix it if it is affected.

What it is: CVE-2026-65600 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 22 Jul 2026. 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-2026-65600 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.23, 3.7.7
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.23
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.23
- github.com/traefik/traefik/v3 (Go): affected from 3.7.0; fixed in 3.7.7
- github.com/traefik/traefik/v3 (Go): affected from 3.7.0; fixed in 3.7.7
- github.com/traefik/traefik (Go): affected all versions; no fix listed
- github.com/traefik/traefik (Go): affected all versions up to 1.7.34; no fix listed
- github.com/traefik/traefik (Go): affected all versions up to 1.7.34; no fix listed
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.52
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.52
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.52

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-2026-65600/ (Markdown: https://insights.sbomify.com/CVE-2026-65600/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-65600
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65600
- OSV: https://osv.dev/vulnerability/CVE-2026-65600

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-65600/
Summaries are generated and may contain mistakes; the official description above is the record.