How severe is CVE-2025-43864?

CVE-2025-43864 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-43864?

CVE-2025-43864 affects the following packages: react-router (npm). Ecosystems affected: npm.

How do I fix CVE-2025-43864?

Update react-router to 7.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-43864 is resolved across your whole dependency graph.

How do I detect CVE-2025-43864 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-router. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2025-43864 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2025-43864?

O3 pinpoints whether CVE-2025-43864 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2025-43864 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-43864 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-43864?

CVE-2025-43864 has an EPSS (Exploit Prediction Scoring System) score of 22.0%, placing it in the 97th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

When was CVE-2025-43864 published, and has it been updated?

CVE-2025-43864 was published on April 25, 2025 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-43864: react-router (High 7.5)

EPSS Exploitation Probability

via FIRST.org ↗

22.0%probability of exploitation in next 30 days

Moderate Risk97th percentile+21.62%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

📦react-router

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

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 Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`react-router`	≥ 7.2.0&&< 7.5.2	7.5.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-router. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update react-router to 7.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-43864 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-43864 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2025-43864. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is CVE-2025-43864 in your dependencies?

O3 detects CVE-2025-43864 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2025-43864