# CVE-2026-41181: Traefik: Errors middleware forwards Authorization and Cookie headers to separate error page service > Traefik's errors middleware leaks sensitive headers like Authorization and Cookie to error page services, exposing user credentials to unintended infrastructure. - **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/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:** 15 May 2026 - **Updated:** 16 May 2026 - **Also known as:** CLEANSTART-2026-MZ53124, GHSA-p6hg-qh38-555r, GO-2026-5532, MINI-3ffm-m726-x3rp, MINI-725w-72xx-rh8w, MINI-hcqc-4x7j-73r9, openSUSE-SU-2026:10713-1, openSUSE-SU-2026:10714-1 ## What is CVE-2026-41181? CVE-2026-41181 is a medium-severity vulnerability in Traefik Traefik, published on 15 May 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 2.11.44, 3.6.15, and 3.7.0-rc.3, there is an information disclosure vulnerability in Traefik's errors (custom error pages) middleware. When the backend returns a response matching the configured status range, the middleware forwards the original request's complete header set, including Authorization, Cookie, and other authentication material, to the separate error page service rather than only the minimal context needed to render the error page. This behavior is undocumented: the documentation states only that Host is forwarded by default, so operators are not warned that sensitive credentials are shared across service boundaries. Deployments using the errors middleware with a distinct error page service may inadvertently expose end-user credentials to infrastructure that was not intended to receive them. This vulnerability is fixed in 2.11.44, 3.6.15, and 3.7.0-rc.3. Weakness: CWE-201 (Insertion of Sensitive Information Into Sent Data) ## Which versions are affected by CVE-2026-41181? 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 | 3.6.15, 3.7.0-rc.3 | | `github.com/traefik/traefik/v3` | Go | All versions | 3.6.15 | | `github.com/traefik/traefik/v3` | Go | All versions | 3.6.15 | | `github.com/traefik/traefik/v3` | Go | From 3.7.0-rc.0 | 3.7.0-rc.3 | | `github.com/traefik/traefik/v3` | Go | From 3.7.0-rc.0 | 3.7.0-rc.3 | | `github.com/traefik/traefik` | Go | All versions | None | | `github.com/traefik/traefik/v2` | Go | All versions | 2.11.44 | | `github.com/traefik/traefik/v2` | Go | All versions | 2.11.44 | | `github.com/traefik/traefik/v2` | Go | All versions | 2.11.44 | | `traefik` | openSUSE:Tumbleweed | All versions | 3.6.16-1.1 | | `traefik2` | openSUSE:Tumbleweed | All versions | 2.11.45-1.1 | Products: Traefik Traefik. ## How do I fix CVE-2026-41181? Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.15 or 3.7.0-rc.3. ## Is CVE-2026-41181 being exploited? There is no known exploitation of CVE-2026-41181 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-2026-41181 and fix it if it is affected. What it is: CVE-2026-41181 is a medium-severity vulnerability in Traefik Traefik, published on 15 May 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-2026-41181 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.15, 3.7.0-rc.3 - github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.15 - github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.15 - github.com/traefik/traefik/v3 (Go): affected from 3.7.0-rc.0; fixed in 3.7.0-rc.3 - github.com/traefik/traefik/v3 (Go): affected from 3.7.0-rc.0; fixed in 3.7.0-rc.3 - github.com/traefik/traefik (Go): affected all versions; no fix listed - github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.44 - github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.44 - github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.44 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-2026-41181/ (Markdown: https://insights.sbomify.com/CVE-2026-41181/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41181 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41181 - OSV: https://osv.dev/vulnerability/CVE-2026-41181 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-41181/ Summaries are generated and may contain mistakes; the official description above is the record.