CVE-2025-29927
Description
A flaw was found in Next.js package. This vulnerability allows bypassing authorization checks within a Next.js application if the authorization check occurs in middleware.
Statement
This vulnerability is rated as Critical impact, rather than Important, because it allows complete authorization bypass in affected Next.js versions. Attackers can circumvent middleware-based authentication and access protected routes simply by including a specific HTTP header (x-middleware-subrequest). This bypasses all security controls implemented in middleware, granting unauthorized access to sensitive application functionality, including admin panels and restricted resources.
Red Hat Enterprise Linux is not affected by this vulnerability as the authorization functionality of Next.js is not in use and the component is only used at build time.
Red Hat Enterprise Linux AI is not affected since the listed components Pathservice and UI are not provided to the customers.
Red Hat Trusted Artifact Signer and Streams for Apache Kafka 2 are not affected by this vulnerability as they do not use Next.js for any authorization functionality.
Mitigation
Block or drop external user requests which contain the x-middleware-subrequest header from reaching your Next.js application.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 9.1 | N/A | 9.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
An attacker could read sensitive data, either by reading the data directly from a data store that is not properly restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity
Technical Impact: Modify Application Data; Modify Files or Directories
An attacker could modify sensitive data, either by writing the data directly to a data store that is not properly restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control
Technical Impact: Gain Privileges or Assume Identity; Execute Unauthorized Code or Commands
When access control checks are not applied consistently - or not at all - an attacker could gain privileges and execute unauthorized code or commands by modifying or reading critical data directly, or by accessing insufficiently-protected, privileged functionality.
Frequently Asked Questions
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