Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:N) | Network: reachable remotely |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:P) | Attack requirements present |
| Privileges required (PR:N) | No privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:L) | Low integrity impact |
| Availability (VA:N) | No availability impact |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
About Vercel Next.Js
CVE-2026-64642 affects Vercel Next.Js, a product from Vercel. Before acting, confirm where Vercel Next.Js runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: Next.js is a React framework for building full-stack web applications. In versions 16.0.0 through 16.2.10, crafted requests targeting Next.js applications using App Router built with Turbopack and a single entry in config.i18n.locales can bypass middleware/proxy based authentication. This issue has been fixed in version 16.2.11.
The weakness class is Improper Authorization. The software does not check whether a user is allowed to perform an action.
Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Vercel Next.Js |
| Affected versions | Next.Js from 16.0.0 before 16.2.11 |
| Published | Jul 27, 2026 |
| Last modified | Jul 29, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | security-advisories@github.com |
How to detect it
- Inventory every instance of Vercel Next.Js and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Vercel Next.Js named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Vercel Next.Js to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-285: Improper Authorization More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
Next.js is a React framework for building full-stack web applications. In versions 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10, crafted requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive CPU usage blocking processing of further requests in the same process. This issue has been fixed in versions 15.5.21 and 16.2.11.
Turborepo is a high-performance build system for JavaScript and TypeScript codebases. Prior to 2.9.14000, the Turborepo LSP VS Code extension could execute shell commands derived from workspace-controlled values. The extension used string-based command execution for Turborepo daemon commands and task runs. A malicious workspace could provide crafted values through workspace settings or task names in the repository's source code that were interpolated into shell commands. When the extension activated or when a user ran a task through the extension, those values could be interpreted by the user's shell, allowing arbitrary command execution with the privileges of the local VS Code process. This vulnerability is fixed in 2.9.14000.
PolarLearn is a free and open-source learning program. In 0-PRERELEASE-16 and earlier, the group chat WebSocket at wss://polarlearn.nl/api/v1/ws can be used without logging in. An unauthenticated client can subscribe to any group chat by providing a group UUID, and can also send messages to any group. The server accepts the message and stores it in the group’s chatContent, so this is not just a visual spam issue.
In addInputMethodListener of com.android.server.inputmethod.InputMethodManagerService, there is a missing permission check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
Improper authorization in Azure AI Foundry allows an unauthorized attacker to elevate privileges over a network.
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