CVE-2026-34077 | React Router vulnerable to Denial of Service via reflected user input in single-fetch

React Router is a router for React. In versions 7.7.0 through 7.13.1, when using React Router's unstable React Server Components (RSC) APIs, there is a potential client-side Cross-Site Scripting (XSS) vulnerability in the RSC redirect handling if redirects come from untrusted sources. This does not impact applications that are not using the unstable RSC APIs in React Router. This is patched in version 7.13.2.

Published: 2026-06-02 Last update: 2026-06-04 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-34077 is rated Low Risk (36.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.06%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-34077

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-08 0.04% 0.06% +0.02%
2 2026-06-03 — 0.04% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34077

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-34077

GitHub Security Advisory for CVE-2026-34077

GHSA-rxv8-25v2-qmq8 · Severity: high · Ecosystem: npm — React Router vulnerable to Denial of Service via reflected user input in single-fetch

OS Trackers for CVE-2026-34077

vendor priority summary link
suse medium — https://www.suse.com/security/cve/CVE-2026-34077/

Affected software / configurations for CVE-2026-34077

Vendor Product Version Raw CPE
shopify react-router >= 7.0.0, < 7.14.0 cpe:2.3:a:shopify:react-router:*:*:*:*:*:node.js:*:*
turbo-stream turbo_stream < 3.0.0 cpe:2.3:a:turbo-stream:turbo_stream:*:*:*:*:*:node.js:*:*

References for CVE-2026-34077

cvelogic Threat Intelligence