CVE-2026-23869
ADVISORY - githubSummary
Impact
A denial of service vulnerability exists in React Server Components, affecting the following packages: react-server-dom-parcel, react-server-dom-turbopack, react-server-dom-webpack versions 19.0.0, 19.1.0 and 19.2.0. The vulnerability is triggered by sending specially crafted HTTP requests to Server Function endpoints.
The payload of the HTTP request causes excessive CPU usage for up to a minute ending in a thrown error that is catchable.
We recommend updating immediately.
The vulnerability exists in versions 19.0.0 through 19.0.4, 19.1.0 through 19.1.5, and 19.2.0 through 19.2.4 of:
react-server-dom-webpack react-server-dom-parcel react-server-dom-turbopack
Patches
Fixes were back ported to versions 19.0.5, 19.1.6, and 19.2.5.
If you are using any of the above packages please upgrade to any of the fixed versions immediately.
If your app’s React code does not use a server, your app is not affected by this vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.
References
See the blog post for more information and upgrade instructions.
Common Weakness Enumeration (CWE)
GitHub
CVSS SCORE
7.5high| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| react-server-dom-webpack | npm | - | - | >=19.2.0,<19.2.5 | 19.2.5 |
| react-server-dom-parcel | npm | - | - | >=19.0.0,<19.0.5 | 19.0.5 |
| react-server-dom-parcel | npm | - | - | >=19.1.0,<19.1.6 | 19.1.6 |
| react-server-dom-parcel | npm | - | - | >=19.2.0,<19.2.5 | 19.2.5 |
| react-server-dom-turbopack | npm | - | - | >=19.0.0,<19.0.5 | 19.0.5 |
| react-server-dom-turbopack | npm | - | - | >=19.1.0,<19.1.6 | 19.1.6 |
| react-server-dom-turbopack | npm | - | - | >=19.2.0,<19.2.5 | 19.2.5 |
| react-server-dom-webpack | npm | - | - | >=19.0.0,<19.0.5 | 19.0.5 |
| react-server-dom-webpack | npm | - | - | >=19.1.0,<19.1.6 | 19.1.6 |
CVSS:3 Severity and metrics
The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification.
The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).
Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.
The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
The vulnerable system can be exploited without interaction from any user.
An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
There is no loss of confidentiality.
There is no loss of trust or accuracy within the impacted component.
There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component.