# CVE-2026-48020: Traefik StripPrefix Route-Level Auth Bypass via Path Normalization > An unauthenticated attacker can bypass route-level authentication in Traefik by exploiting path normalization flaws in the StripPrefix middleware to access protected backend endpoints. - **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:** 23 Jun 2026 - **Updated:** 2 Sep 2026 - **Also known as:** CLEANSTART-2026-RL56372, GHSA-xf64-8mw2-4gr2, GO-2026-5752, MINI-3qcf-p94h-gmv5, MINI-rh4v-8hcm-54rw, MINI-xh66-5gj9-5h7q, openSUSE-SU-2026:11045-1 ## What is CVE-2026-48020? CVE-2026-48020 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### 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. Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-288 (Authentication Bypass Using an Alternate Path or Channel) ## Which versions are affected by CVE-2026-48020? 9 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 | 3.6.19, 3.7.3 | | `github.com/traefik/traefik/v3` | Go | All versions | 3.6.19 | | `github.com/traefik/traefik/v3` | Go | All versions | 3.6.19 | | `github.com/traefik/traefik/v3` | Go | From 3.7.0-ea.1 | 3.7.3 | | `github.com/traefik/traefik/v3` | Go | From 3.7.0-ea.1 | 3.7.3 | | `github.com/traefik/traefik` | Go | All versions | None | | `github.com/traefik/traefik/v2` | Go | All versions | 2.11.48 | | `github.com/traefik/traefik/v2` | Go | All versions | 2.11.48 | | `github.com/traefik/traefik/v2` | Go | All versions | 2.11.48 | | `traefik2` | openSUSE:Tumbleweed | All versions | 2.11.50-1.1 | Products: Traefik Traefik. ## How do I fix CVE-2026-48020? Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.19 or 3.7.3. ## Is CVE-2026-48020 being exploited? There is no known exploitation of CVE-2026-48020 in the wild and no public exploit code. Public exploit code: - https://github.com/Hunt-Benito/traefik-stripprefix-auth-bypass-cve-2026-48020-path-normalization (github_poc): https://github.com/Hunt-Benito/traefik-stripprefix-auth-bypass-cve-2026-48020-path-normalization ## 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-2026-48020 and fix it if it is affected. What it is: CVE-2026-48020 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 23 Jun 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-2026-48020 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.19, 3.7.3 - github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.19 - github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.19 - github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.3 - github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.3 - github.com/traefik/traefik (Go): affected all versions; no fix listed - github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.48 - github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.48 - github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.48 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-2026-48020/ (Markdown: https://insights.sbomify.com/CVE-2026-48020/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48020 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48020 - OSV: https://osv.dev/vulnerability/CVE-2026-48020 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-48020/ Summaries are generated and may contain mistakes; the official description above is the record.