What is CVE-2026-42211?

CVE-2026-42211 is a high-severity vulnerability in Remix-run React-router, classified under Deserialization of Untrusted Data. CVSS score: 8.1/10. Published 2026-06-02.

How severe is CVE-2026-42211?

High severity. CVSS v3 base score is 8.1 out of 10.

Deserialization in Remix-run React-router

CVE-2026-42211

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 ap…

Vulnerability class: Insecure Deserialization

EPSS: 0.003 (48.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Remix-run React-router — versions >= 7.0.0, < 7.14.2
Shopify React-router

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42211?: CVE-2026-42211 is a high-severity vulnerability in Remix-run React-router, classified under Deserialization of Untrusted Data. CVSS score: 8.1/10. Published 2026-06-02.
How severe is CVE-2026-42211?: High severity. CVSS v3 base score is 8.1 out of 10.