# CVE-2026-42342: React Router vulnerable to DoS via unbounded path expansion in __manifest endpoint > Crafted requests cause resource exhaustion in React Router Framework Mode, leading to service unavailability; upgrade to patched versions. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 2 Jun 2026 - **Updated:** 3 Jun 2026 - **Also known as:** CLSA-2026-1784943129, CLSA-2026-1789118116, CLSA-2026-1792160940, CLSA-2026-1792253399, CLSA-2026-1792279965, CLSA-2026-1792419114, CLSA-2026-1792419190, CLSA-2026-1792419270, CLSA-2026-1792419626, CLSA-2026-1792421944, CLSA-2026-1792424733, CLSA-2026-1792425408, CLSA-2026-1792428109, CLSA-2026-1792430033, GHSA-8x6r-g9mw-2r78, MINI-7p24-7ppq-pvfr, ROOT-APP-NPM-CVE-2026-42342 ## What is CVE-2026-42342? CVE-2026-42342 is a high-severity denial of service vulnerability in @remix-run/server-runtime, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description React Router is a router for React. In versions 7.0.0 through 7.14.x of react-router and versions 2.10.0 through 2.17.4 of @remix-run/server-runtime, certain crafted requests can consume disproportionate server resources via unbounded path expansion in the __manifest endpoint, resulting in response time degradation and/or service unavailability for end users. This affects React Router Framework Mode applications as well as Remix applications. This does not impact applications using Declarative Mode (``) or Data Mode (`createBrowserRouter/`). This is patched in react-router version 7.15.0 and @remix-run/server-runtime version 2.17.5. Weakness: CWE-400 (Uncontrolled Resource Consumption) ## Which versions are affected by CVE-2026-42342? 4 open source packages ship an affected version, including @remix-run/server-runtime and react-router. It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `@remix-run/server-runtime` | npm | From 2.10.0 | 2.17.5 | | `@remix-run/server-runtime` | npm | From 2.10.0 | 2.17.5 | | `react-router` | npm | From 7.0.0 | 7.15.0 | | `react-router` | npm | From 7.0.0 | 7.15.0 | Products: Shopify React-Router, Shopify Remix-Run\/Server-Runtime. ## How do I fix CVE-2026-42342? Upgrade @remix-run/server-runtime to 2.17.5 or later. ## Is CVE-2026-42342 being exploited? There is no known exploitation of CVE-2026-42342 in the wild and no public exploit code. ## Other vulnerabilities in @remix-run/server-runtime - [CVE-2026-55685](https://insights.sbomify.com/CVE-2026-55685/): React Router: Unauthenticated Denial of Service via Inefficient Route Matching (high 8.7) - [CVE-2026-21884](https://insights.sbomify.com/CVE-2026-21884/): React Router SSR XSS in ScrollRestoration (high 8.2) - [CVE-2026-42211](https://insights.sbomify.com/CVE-2026-42211/): React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE (high 8.1) - [CVE-2026-33245](https://insights.sbomify.com/CVE-2026-33245/): React Router vulnerable to XSS in unstable RSC redirect handling via javascript: redirect targets (high 8.0) - [CVE-2026-22029](https://insights.sbomify.com/CVE-2026-22029/): React Router vulnerable to XSS via Open Redirects (high 8.0) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-42342 and fix it if it is affected. What it is: CVE-2026-42342 is a high-severity denial of service vulnerability in @remix-run/server-runtime, published on 2 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-2026-42342 in the wild and no public exploit code. Affected packages and fixed versions: - @remix-run/server-runtime (npm): affected from 2.10.0; fixed in 2.17.5 - @remix-run/server-runtime (npm): affected from 2.10.0; fixed in 2.17.5 - react-router (npm): affected from 7.0.0; fixed in 7.15.0 - react-router (npm): affected from 7.0.0; fixed in 7.15.0 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-2026-42342/ (Markdown: https://insights.sbomify.com/CVE-2026-42342/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42342 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42342 - OSV: https://osv.dev/vulnerability/CVE-2026-42342 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-42342/ Summaries are generated and may contain mistakes; the official description above is the record.