New React RSC Vulnerabilities Enable DoS and Source Code Exposure

The React team has released fixes for two new types of flaws in React Server Components (RSC) that, if successfully exploited, could result in denial-of-service (DoS) or source code exposure. The team said the issues were found by the security community while attempting to exploit the patches released for CVE-2025-55182 (CVSS score: 10.0), a critical bug in RSC that has since been weaponized in
[[{“value”:”

The React team has released fixes for two new types of flaws in React Server Components (RSC) that, if successfully exploited, could result in denial-of-service (DoS) or source code exposure.

The team said the issues were found by the security community while attempting to exploit the patches released for CVE-2025-55182 (CVSS score: 10.0), a critical bug in RSC that has since been weaponized in the wild.

The three vulnerabilities are listed below –

  • CVE-2025-55184 (CVSS score: 7.5) – A pre-authentication denial of service vulnerability arising from unsafe deserialization of payloads from HTTP requests to Server Function endpoints, triggering an infinite loop that hangs the server process and may prevent future HTTP requests from being served
  • CVE-2025-67779 (CVSS score: 7.5) – An incomplete fix for CVE-2025-55184 that has the same impact
  • CVE-2025-55183 (CVSS score: 5.3) – An information leak vulnerability that may cause a specifically crafted HTTP request sent to a vulnerable Server Function to return the source code of any Server Function

However, successful exploitation of CVE-2025-55183 requires the existence of a Server Function that explicitly or implicitly exposes an argument that has been converted into a string format.

Cybersecurity

The flaws affecting the following versions of react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack –

  • CVE-2025-55184 and CVE-2025-55183 – 19.0.0, 19.0.1 19.1.0, 19.1.1, 19.1.2, 19.2.0 and 19.2.1
  • CVE-2025-67779 – 19.0.2, 19.1.3 and 19.2.2

Security researcher RyotaK and Shinsaku Nomura have been credited with reporting the two DoS bugs to the Meta Bug Bounty program, while Andrew MacPherson has been acknowledged for reporting the information leak flaw.

Users are advised to update to versions 19.0.3, 19.1.4, and 19.2.3 as soon as possible, particularly in light of active exploration of CVE-2025-55182.

“When a critical vulnerability is disclosed, researchers scrutinize adjacent code paths looking for variant exploit techniques to test whether the initial mitigation can be bypassed,” the React team said. “This pattern shows up across the industry, not just in JavaScript. Additional disclosures can be frustrating, but they are generally a sign of a healthy response cycle.”

Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post.

“}]] The Hacker News 

Total
0
Shares
Previous Post

React2Shell Exploitation Escalates into Large-Scale Global Attacks, Forcing Emergency Mitigation

Next Post

Securing GenAI in the Browser: Policy, Isolation, and Data Controls That Actually Work

Related Posts

⚡ Weekly Recap: Apple 0-Days, WinRAR Exploit, LastPass Fines, .NET RCE, OAuth Scams & More

If you use a smartphone, browse the web, or unzip files on your computer, you are in the crosshairs this week. Hackers are currently exploiting critical flaws in the daily software we all rely on—and in some cases, they started attacking before a fix was even ready. Below, we list the urgent updates you need to install right now to stop these active threats. ⚡ Threat of the Week Apple and
Read More

Fortinet Fixes Critical FortiSIEM Flaw Allowing Unauthenticated Remote Code Execution

Fortinet has released updates to fix a critical security flaw impacting FortiSIEM that could allow an unauthenticated attacker to achieve code execution on susceptible instances. The operating system (OS) injection vulnerability, tracked as CVE-2025-64155, is rated 9.4 out of 10.0 on the CVSS scoring system. "An improper neutralization of special elements used in an OS command ('OS command
Read More

Cisco Warns of Active Attacks Exploiting Unpatched 0-Day in AsyncOS Email Security Appliances

Cisco has alerted users to a maximum-severity zero-day flaw in Cisco AsyncOS software that has been actively exploited by a China-nexus advanced persistent threat (APT) actor codenamed UAT-9686 in attacks targeting Cisco Secure Email Gateway and Cisco Secure Email and Web Manager. The networking equipment major said it became aware of the intrusion campaign on December 10, 2025, and that it
Read More