CVE-2025-61686

CVE-2025-61686 is a critical-severity vulnerability in Shopify React-router/node with a CVSS 3.x base score of 9.1. Its EPSS exploit-prediction score of 16% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-22.

Key facts

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.

Frequently asked questions

What is CVE-2025-61686?
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.
How severe is CVE-2025-61686?
CVE-2025-61686 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2025-61686 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 16% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-61686?
CVE-2025-61686 primarily affects Shopify React-router/node. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-61686?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-61686 have an EU (EUVD) identifier?
Yes. CVE-2025-61686 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1468.
When was CVE-2025-61686 published?
CVE-2025-61686 was published on 2026-01-10 and last updated on 2026-06-27.

References

Affected products (3)

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