SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2025-31137

There is a vulnerability in Remix/React Router that affects all Remix 2 and React Router 7 consumers using the Express adapter.

HIGH 7.5EPSS 1.16%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.16%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

React Router is a multi-strategy router for React bridging the gap from React 18 to React 19. There is a vulnerability in Remix/React Router that affects all Remix 2 and React Router 7 consumers using the Express adapter. Basically, this vulnerability allows anyone to spoof the URL used in an incoming Request by putting a URL pathname in the port section of a URL that is part of a Host or X-Forwarded-Host header sent to a Remix/React Router request handler. This issue has been patched and released in Remix 2.16.3 and React Router 7.4.1.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
1.16% probability · 65th percentile
CISA KEV
Not listed
Weakness
CWE-444
Source
security-advisories@github.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.