# Next.js is vulnerable to RCE in React flight protocol

Advisory record · `GHSA-9qr9-h5gf-34mp`

- **Identifiers:** `GHSA-9qr9-h5gf-34mp` · `CVE-2025-55182`
- **State:** Confirmed
- **Severity:** CVSS 10.0 Critical
- **Critical:** Yes: KEV, CVSS 9+, CVSS 7+ and EPSS
- **Weakness (CWE):** [CWE-502](https://cwe.mitre.org/data/definitions/502.html)
- **Tags:** [Insecure deserialization](https://agentprime.io/advisories/tag/deserialization.md)
- **Published:** 3 Dec 2025
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 3 Dec 2025, 19:07 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- In CISA’s KEV catalogue since 5 Dec 2025: it is known to be exploited.
- CVSS score 10.0: 9.0 or more.
- CVSS score 10.0 (7.0 or more) and EPSS 1.00 (0.1 or more): a high score and a real chance of exploitation in the next 30 days.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `next` (npm): affected `>=14.3.0-canary.77, <15.0.5 || >=15.1.0-canary.0, <15.1.9 || >=15.2.0-canary.0, <15.2.6 || >=15.3.0-canary.0, <15.3.6 || >=15.4.0-canary.0, <15.4.8 || >=15.5.0-canary.0, <15.5.7 || >=16.0.0-canary.0, <16.0.7`; fixed in `15.0.5`, `15.1.9`, `15.2.6`, `15.3.6`, `15.4.8`, `15.5.7`, `16.0.7`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 10.0 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`, from CNA (Meta)

- **CISA KEV:** Listed since 5 Dec 2025: known to be exploited. CISA reports use in ransomware campaigns.
- **EPSS:** 1.00, the 99th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 3 Dec 2025, 15:43 UTC: [Published by the maintainers as a GitHub repository advisory](https://github.com/vercel/next.js/security/advisories/GHSA-9qr9-h5gf-34mp)

## Sources

- [GitHub Advisory Database: GHSA-9qr9-h5gf-34mp](https://github.com/advisories/GHSA-9qr9-h5gf-34mp)
- [OSV: GHSA-9qr9-h5gf-34mp](https://osv.dev/vulnerability/GHSA-9qr9-h5gf-34mp)
- <https://github.com/facebook/react/security/advisories/GHSA-fv66-9v8q-g76r>
- <https://github.com/vercel/next.js/security/advisories/GHSA-9qr9-h5gf-34mp>
- <https://github.com/vitejs/vite-plugin-react/security/advisories/GHSA-fmh4-wr37-44fp>
- <https://nvd.nist.gov/vuln/detail/CVE-2025-55182>
- <https://github.com/vercel/next.js>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-9qr9-h5gf-34mp>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-9qr9-h5gf-34mp/>. Everything for agents: <https://agentprime.io/llms.txt>.