CVE-2025-61686

Published Jan 10, 2026

Last updated 5 hours ago

React Router

Overview

AI description

Automated description summarized from trusted sources.

CVE-2025-61686 is a path traversal vulnerability found in React Router and Remix frameworks. The flaw specifically impacts the `createFileSessionStorage()` function when it is used with unsigned cookies. Attackers can exploit this by crafting malicious session cookies containing directory traversal sequences, which could allow them to read from or write to locations outside the designated session file directory. This vulnerability affects `@react-router/node` versions 7.0.0 through 7.9.3, `@remix-run/node` prior to version 2.17.2, and `@remix-run/deno` prior to version 2.17.2. While an attacker could potentially access sensitive server files, successful exploitation for reading files is limited to those that match the expected session file format. The issue has been addressed in `@react-router/node` version 7.9.4, `@remix-run/deno` version 2.17.2, and `@remix-run/node` version 2.17.2.

Description: React Router is a router for React. In @react-router/node versions 7.0.0 through 7.9.3, @remix-run/deno prior to version 2.17.2, and @remix-run/node prior to version 2.17.2, if createFileSessionStorage() is being used from @react-router/node (or @remix-run/node/@remix-run/deno in Remix v2) with an unsigned cookie, it is possible for an attacker to cause the session to try to read/write from a location outside the specified session file directory. The success of the attack would depend on the permissions of the web server process to access those files. Read files cannot be returned directly to the attacker. Session file reads would only succeed if the file matched the expected session file format. If the file matched the session file format, the data would be populated into the server side session but not directly returned to the attacker unless the application logic returned specific session information. This issue has been patched in @react-router/node version 7.9.4, @remix-run/deno version 2.17.2, and @remix-run/node version 2.17.2.
Source: security-advisories@github.com
NVD status: Awaiting Analysis

Risk scores

CVSS 3.1

Type: Secondary
Base score: 9.1
Impact score: 5.2
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Severity: CRITICAL

Weaknesses

security-advisories@github.com: CWE-22

Hype score: Not currently trending

References