# CVE-2026-88008: Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization > Traefik fails to apply authorization and security controls to HTTP/2 requests after an h2c upgrade, allowing unauthenticated access to protected backend paths. - **Severity:** High 7.0 (`CVSS:4.0/AV:N/AC:L/AT:P/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:** 10 Sep 2026 - **Updated:** 10 Sep 2026 - **Also known as:** ECHO-6de7-ef62-5b7d, GHSA-w4v4-9rw7-5326, GO-2026-6468, MINI-33wc-jmw5-h843, MINI-cjqg-pwmc-cjr3, MINI-mghp-9pwm-cmf9 ## What is CVE-2026-88008? CVE-2026-88008 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 10 Sep 2026. 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. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching Protocols, Traefik enters a raw tunnel and no longer applies routers, BasicAuth, ForwardAuth, IPAllowList, RateLimit, access logging, metrics, or tracing to later HTTP/2 requests, allowing an unauthenticated request through an unprotected route to reach protected paths on the same backend. This issue is fixed in 2.11.57 and 3.7.13. Weakness: CWE-863 (Incorrect Authorization), CWE-444 (Inconsistent Interpretation of HTTP Requests) ## Which versions are affected by CVE-2026-88008? 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 | From 2.11.26 | 2.11.57 | | `github.com/traefik/traefik/v2` | Go | From 2.11.26 | 2.11.57 | | `github.com/traefik/traefik/v2` | Go | From 2.11.26 | 2.11.57 | | `github.com/traefik/traefik` | Go | All versions | None | | `github.com/traefik/traefik/v3` | Go | From 3.4.2 | 3.7.13 | | `github.com/traefik/traefik/v3` | Go | From 3.4.2 | 3.7.13 | | `github.com/traefik/traefik/v3` | Go | From 3.4.2 | 3.7.13 | Products: Traefik Traefik. ## How do I fix CVE-2026-88008? Upgrade github.com/traefik/traefik/v2 to 2.11.57 or later. ## Is CVE-2026-88008 being exploited? There is no known exploitation of CVE-2026-88008 in the wild and no public exploit code. Public exploit code: - CVE-2026-88008 - Traefik (<=2.11.56 / <=3.7.12): a client-controlled h2c upgrade tunnels past routers and middleware (BasicAuth/ForwardAuth/IPAllowList), unauthorised access + no access logging. Stdlib-only Python PoC + real Jetty h2c lab, verified on v3.7.12 vs v3.7.13. (github_poc): https://github.com/Boreas37/CVE-2026-88008-PoC ## 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-2026-88008 and fix it if it is affected. What it is: CVE-2026-88008 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 10 Sep 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-2026-88008 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/traefik/traefik/v2 (Go): affected from 2.11.26; fixed in 2.11.57 - github.com/traefik/traefik/v2 (Go): affected from 2.11.26; fixed in 2.11.57 - github.com/traefik/traefik/v2 (Go): affected from 2.11.26; fixed in 2.11.57 - github.com/traefik/traefik (Go): affected all versions; no fix listed - github.com/traefik/traefik/v3 (Go): affected from 3.4.2; fixed in 3.7.13 - github.com/traefik/traefik/v3 (Go): affected from 3.4.2; fixed in 3.7.13 - github.com/traefik/traefik/v3 (Go): affected from 3.4.2; fixed in 3.7.13 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-2026-88008/ (Markdown: https://insights.sbomify.com/CVE-2026-88008/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-88008 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-88008 - OSV: https://osv.dev/vulnerability/CVE-2026-88008 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-88008/ Summaries are generated and may contain mistakes; the official description above is the record.