Medium 5.4Published Mar 18, 2026

CVE-2026-27977Next.js is a React framework for building full-stack web applications.

Updated under an hour ago (2026-10-19 09:10 UTC)

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It affects vercel next.js. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for vercel next.js

Exploited in the last 30 days

Next.js is a React framework for building full-stack web applications. Starting in version 16.0.1 and prior to version 16.1.7, in `next dev`, cross-site protection for internal websocket endpoints could treat `Origin: null` as a bypass case even if `allowedDevOrigins` is configured, allowing privacy-sensitive/opaque contexts (for example sandboxed documents) to connect unexpectedly. If a dev server is reachable from attacker-controlled content, an attacker may be able to connect to the HMR websocket channel and interact with dev websocket traffic. This affects development mode only. Apps without a configured `allowedDevOrigins` still allow connections from any origin. The issue is fixed in version 16.1.7 by validating `Origin: null` through the same cross-site origin-allowance checks used for other origins. If upgrading is not immediately possible, do not expose `next dev` to untrusted networks and/or block websocket upgrades to `/_next/webpack-hmr` when `Origin` is `null` at the proxy.

CVSS: 5.4 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Weakness (CWE): CWE-1385
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

vercel next.js vercel:next.js	from 16.0.1 before 16.1.7	NVD

References

https://github.com/vercel/next.js/commit/862f9b9bb41d235e0d8cf44aa811e7fd118cee2apatch
https://github.com/vercel/next.js/releases/tag/v16.1.7release-notes
https://github.com/vercel/next.js/security/advisories/GHSA-jcc7-9wpm-mj36mitigation, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.