What’s Vulnerable › Vulnerabilities

CVE-2025-43864: React Router allows a DoS via cache poisoning by forcing SPA mode

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 20.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-04-25 · updated 2026-06-17
• Weakness: CWE-755

Description

React Router is a router for React. Starting in version 7.2.0 and prior to version 7.5.2, it is possible to force an application to switch to SPA mode by adding a header to the request. If the application uses SSR and is forced to switch to SPA, this causes an error that completely corrupts the page. If a cache system is in place, this allows the response containing the error to be cached, resulting in a cache poisoning that strongly impacts the availability of the application. This issue has been patched in version 7.5.2.

Affected products

• remix-run react-router: from 7.2.0, < 7.5.2

References

• https://github.com/remix-run/react-router/blob/e6c53a0130559b4a9bd47f9cf76ea5b08a69868a/packages/react-router/lib/server-runtime/server.ts#L407
• https://github.com/remix-run/react-router/commit/c84302972a152d851cf5dd859ff332b354b70111
• https://github.com/remix-run/react-router/security/advisories/GHSA-f46r-rw29-r322

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