Skip to content
Fencer Intel
low 3.7

CVE-2025-49005 json

Next.js cache poisoning due to omission of Vary header

published last yr. modified last mo. also EUVD-2025-19911 , GHSA-r2fc-ccr8-96c4

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm next 15.3.3
  • vercel next.js 15.3.3
  • vercel vercel 42.3.0

Is CVE-2025-49005 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-49005 updated cvss 3.7

nextjs: Next.js cache poisoning

  • Red Hat Enterprise Linux 7 firefox Red Hat Enterprise Linux 8 firefox, thunderbird Red Hat Enterprise Linux 9 firefox, dotnet7.0, dotnet-host, firefox-x11, thunderbird, dotnet-sdk-7.0, +9 more Red Hat Enterprise Linux 10 firefox, thunderbird Red Hat Enterprise Linux AI (RHEL AI) rhelai1/ui-rhel9, rhelai1/granite-8b-lab-v1, rhelai1/pathservice-rhel9, rhelai1/skills-adapter-v3, rhelai1/granite-7b-starter, rhelai1/docling-serve-rhel9, +23 more
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/vercel/next.js/issues/79346 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm next
>=15.3.0, <15.3.3
15.3.3

Affected products

  • vercel next.js

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of vercel/next.js published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.