CVE-2025-31125 is a security vulnerability that affects Vite, a widely used frontend development and build tool for modern JavaScript applications. Vite is especially popular for its fast development server and efficient build process. However, this vulnerability exposes a weakness in how the Vite development server handles file access when it is made reachable over a network.
At its core, the issue allows unauthenticated remote attackers to read arbitrary files from a system running a vulnerable Vite development server. While Vite is typically used in local development environments, problems arise when developers expose the dev server beyond localhost, intentionally or unintentionally.
Affected Versions :
- affected at >= 6.2.0, < 6.2.4
- affected at >= 6.1.0, < 6.1.3
- affected at >= 6.0.0, < 6.0.13
- affected at >= 5.0.0, < 5.4.16
- affected at < 4.5.11
Vulnerability Description
The vulnerability exists in Vite versions prior to the patched releases. It is classified as an improper access control issue that results in an arbitrary file read condition.
Specifically, the problem lies in the file-serving logic of the Vite development server. Certain URL query parameters—such as ?inline&import or ?raw?import—are not validated correctly. Because of this, an attacker can manipulate requests in a way that bypasses file access restrictions. As a result, files that should never be accessible through the dev server may be exposed.
It is important to note that this vulnerability only affects environments where the Vite dev server is exposed to the network. This typically happens when developers start Vite with options like --host or configure server.host to bind to a public or non-localhost interface. When the dev server is reachable by untrusted users, the risk becomes real.
Impact and Severity
The base severity of CVE-2025-31125 is rated as medium, with a CVSS v3.1 score of approximately 5.3. However, the real-world impact can vary depending on how and where Vite is deployed. In some scenarios—particularly where sensitive files are present—the effective severity may be higher.
The primary impact is unauthorized disclosure of files. An attacker could potentially read:
- Configuration files
- Application source code
- Environment variables or secrets stored in readable files
Because no authentication is required, any remote attacker who can reach the vulnerable dev server may exploit the issue. This makes publicly exposed development environments especially risky, as they often contain sensitive or unfinished code.
Who Is Affected?
This vulnerability affects developers and teams running Vite development servers that are accessible over a network, rather than strictly bound to localhost.
In most standard workflows, Vite is used only during development and is not meant to be exposed publicly. Therefore, production builds are generally not affected, since they consist of static assets served by a separate web server. The risk appears when development servers are mistakenly exposed to the internet or shared networks, such as cloud VMs, containers, or misconfigured internal environments.
Fixes and Mitigations
The Vite team has released patches to address this issue. Developers are strongly encouraged to upgrade to one of the following fixed versions:
- Patched versions
- >=6.2.4
- >=6.1.3, <6.2.0
- >=6.0.13, <6.1.0
- >=5.4.16, <6.0.0
- >=4.5.11, <5.0.0
These versions include corrections that prevent improper file access through crafted requests.
If upgrading immediately is not possible, there are important mitigation steps you should take:
- Restrict the dev server to localhost only
- Avoid using
--hostunless absolutely necessary - Ensure the dev server is not exposed to the public internet
- Use firewalls or network rules to limit access
Classification and References
CVE-2025-31125 is associated with the following Common Weakness Enumerations (CWEs):
- CWE-200 – Exposure of Sensitive Information to an Unauthorized Actor
- CWE-284 – Improper Access Control
The vulnerability is officially listed in the U.S. National Vulnerability Database (NVD) and has also been added to the CISA Known Exploited Vulnerabilities Catalog, signaling that organizations should treat remediation as a priority.
CVE-2025-31125 is an arbitrary file read vulnerability in the Vite development server that can expose sensitive files when the server is accessible from untrusted networks. While it does not typically affect production environments, it poses a real risk to exposed development setups. The safest course of action is to upgrade to a patched version of Vite and ensure that development servers remain private and properly restricted.
