# CVE-2026-75604: Next.js: Unauthenticated Remote Code Execution on windows-hosted servers > Remote attackers can traverse cache paths on Windows Next.js servers to steal encryption keys and execute arbitrary code. - **Severity:** Critical 9.0 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/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:** 1 Sep 2026 - **Updated:** 4 Sep 2026 - **Also known as:** CLEANSTART-2026-LG90193, CLEANSTART-2026-TQ64674, CLSA-2026-1791974962, CLSA-2026-1792195714, CLSA-2026-1792195731, CLSA-2026-1792195754, CLSA-2026-1792195758, CLSA-2026-1792196700, CLSA-2026-1792196729, CLSA-2026-1792196731, CLSA-2026-1792196882, CLSA-2026-1792206274, CLSA-2026-1792206292, CLSA-2026-1792206327, CLSA-2026-1792206331, CLSA-2026-1792256966, CLSA-2026-1792256969, CLSA-2026-1792272207, CLSA-2026-1792272233, CLSA-2026-1792272249, CLSA-2026-1792272251, CLSA-2026-1792292983, CLSA-2026-1792293020, CLSA-2026-1792293021, CLSA-2026-1792293025, CLSA-2026-1792304694, CLSA-2026-1792304724, CLSA-2026-1792304744, CLSA-2026-1792304745, CLSA-2026-1792326279, CLSA-2026-1792326313, CLSA-2026-1792326317, CLSA-2026-1792326318, CLSA-2026-1792338219, CLSA-2026-1792338240, CLSA-2026-1792338242, CLSA-2026-1792338246, CLSA-2026-1792346471, CLSA-2026-1792346491, CLSA-2026-1792358572, CLSA-2026-1792358602, CLSA-2026-1792358604, CLSA-2026-1792358607, CLSA-2026-1792363962, CLSA-2026-1792363989, CLSA-2026-1792363990, CLSA-2026-1792364013, CLSA-2026-1792367392, CLSA-2026-1792367396, ECHO-c99a-939d-6275, GHSA-p293-qw3h-jr36, MINI-6jhj-g3wm-jwvf, MINI-fq94-vg7v-qhp3, MINI-gmwv-jh59-5h8f, MINI-m7x2-4vmh-hwxw, ROOT-APP-NPM-CVE-2026-75604 ## What is CVE-2026-75604? CVE-2026-75604 is a critical path traversal vulnerability in vercel next.js, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Next.js is a React framework for building full-stack web applications. From 13.4.0 until 15.5.24 and 16.3.3, Next.js applications using Pages Router or App Router without Cache Components on Windows-hosted servers do not consistently escape backslashes in route segments before constructing incremental-cache paths. In packages/next/src/shared/lib/router/utils/escape-path-delimiters.ts and packages/next/src/server/lib/incremental-cache/file-system-cache.ts, a remote request can supply encoded Windows path separators that traverse outside the intended cache root and expose private build data, including the server-reference-manifest encryption key. Disclosure of that key can enable remote code execution in the affected application. This issue is fixed in versions 15.5.24 and 16.3.3. Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) ## Which versions are affected by CVE-2026-75604? 4 open source packages ship an affected version, including next. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `next` | npm | From 13.4.0 | 15.5.24 | | `next` | npm | From 13.4.0 | 15.5.24 | | `next` | npm | From 16.0.0 | 16.3.3 | | `next` | npm | From 16.0.0 | 16.3.3 | ## How do I fix CVE-2026-75604? Upgrade next to a fixed version for your release line: 15.5.24 or 16.3.3. ## Is CVE-2026-75604 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75604 exists. Public exploit code: - 🛡 Official AI Security Tool module for CVE-2026-75604 (Next.js Windows Unauthenticated Remote Code Execution) with safe in-app execution, deep vulnerability validation, and DevSecOps-ready security auditing workflows. (github_poc): https://github.com/ZeroDayEvil/CVE-2026-75604-PoC - CVE-2026-75604 Next.js Windows RCE poc (github_poc): https://github.com/rafabd1/CVE-2026-75604-poc - A Python-based exploitation framework for CVE-2026-75604 that enables authorized penetration testers to validate Next.js Windows cache traversal vulnerabilities. Deploys reverse shells and webshells via path traversal, with built-in target verification and proxy support for seamless integration into standard pentest workflows. (github_poc): https://github.com/e4zyy/Project-CVE-2026-75604 - CVE-2026-75604 (Next.js Windows RCE) PoC - unauthenticated RCE via cache path traversal + forged Server Action; for authorized security testing (github_poc): https://github.com/HackSpeak/CVE-2026-75604 - Next.js Unauthenticated RCE on Windows Servers (metasploit) - Research lab and exploit chain for CVE-2026-75604: path traversal in the Next.js incremental cache, to RCE on Windows. (github_poc): https://github.com/FORTBRIDGE-UK/cve-2026-75604 ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-75604 and fix it if it is affected. What it is: CVE-2026-75604 is a critical path traversal vulnerability in vercel next.js, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75604 exists. Affected packages and fixed versions: - next (npm): affected from 13.4.0; fixed in 15.5.24 - next (npm): affected from 13.4.0; fixed in 15.5.24 - next (npm): affected from 16.0.0; fixed in 16.3.3 - next (npm): affected from 16.0.0; fixed in 16.3.3 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-2026-75604/ (Markdown: https://insights.sbomify.com/CVE-2026-75604/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75604 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75604 - OSV: https://osv.dev/vulnerability/CVE-2026-75604 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-75604/ Summaries are generated and may contain mistakes; the official description above is the record.