Denial of Service in React Server Components Server Function Endpoints
CVE-2026-23870 is a high-severity denial-of-service vulnerability in React Server Components affecting the packages react-server-dom-webpack, react-server-dom-parcel, and react-server-dom-turbopack. The issue is triggered when a specially crafted HTTP request is sent to a server function endpoint and processed by the server-side React Server Components request handling and deserialization logic. The affected packages are the bundler integration layers used to serialize and deserialize server function calls over HTTP. Available reporting indicates the flaw is associated with inadequate structural or type constraints during inbound payload deserialization, allowing pathological processing that can drive excessive CPU consumption and, in some cases, server crashes or out-of-memory conditions. Affected versions are 19.0.0 through 19.0.5, 19.1.0 through 19.1.6, and 19.2.0 through 19.2.5.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No valid public exploits. Mallory filtered out 2 candidates as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
16 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A high-severity denial-of-service vulnerability in React Server Components / Next.js App Router caused by unsafe deserialization in the React Flight protocol, allowing crafted requests to trigger excessive CPU usage.
A denial-of-service vulnerability in React Server Components affecting react-server-dom-* packages and impacting Next.js applications that use Server Functions, Partial Prerendering with Cache Components, or the Image Optimization API.
A denial of service vulnerability in React Server Components server function endpoint handling that allows unauthenticated remote attackers to crash servers or exhaust CPU/memory via crafted HTTP requests.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.