Is CVE-2026-42211 in the CISA KEV catalog?

No. CVE-2026-42211 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-42211?

CVE-2026-42211 has a CVSS v3 base score of 8.1 (HIGH).

What is the EPSS score for CVE-2026-42211?

CVE-2026-42211 has an EPSS score of 0.42% (33th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-42211

HIGH

8.1

CVSS v3

NVD

Description

React Router is a router for React. In versions 7.0.0 through 7.14.1, when using Framework Mode, a combination of steps could potentially allow unauthorized remote code execution (RCE) through external requests. This attack requires the application code to have an existing prototype pollution vulnerability, which can then be leveraged in a 2-step attack where the second step triggers unauthorized RCE on the remote server. This does not impact applications using Declarative Mode (`<BrowserRouter>`) or Data Mode (`createBrowserRouter/<RouterProvider>`). This is patched in version 7.14.2.

CWE-502Deserialization of Untrusted Data

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.42%probability of exploitation in 30 days

33rdpercentile

Low risk: more likely to be exploited than 33% of all known CVEs.

References

https://github.com/remix-run/react-router/security/advisories/GHSA-49rj-9fvp-4h2h

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-04.