CVE-2025-49005Next.js cache poisoning due to omission of Vary header

Description

Next.js is a React framework for building full-stack web applications. In Next.js App Router from 15.3.0 to before 15.3.3 and Vercel CLI from 41.4.1 to 42.2.0, a cache poisoning vulnerability was found. The issue allowed page requests for HTML content to return a React Server Component (RSC) payload instead under certain conditions. When deployed to Vercel, this would only impact the browser cache, and would not lead to the CDN being poisoned. When self-hosted and deployed externally, this could lead to cache poisoning if the CDN does not properly distinguish between RSC / HTML in the cache keys. This issue has been resolved in Next.js 15.3.3.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/vercel/next.js/security/advisories/GHSA-r2fc-ccr8-96c4 Vendor Advisory
• https://github.com/vercel/next.js/issues/79346 ExploitIssue Tracking
• https://github.com/vercel/next.js/commit/ec202eccf05820b60c6126d6411fe16766ecc066 Patch
• https://github.com/vercel/next.js/releases/tag/v15.3.3 Release Notes
• https://vercel.com/changelog/cve-2025-49005 Vendor Advisory