# CVE-2026-47874: Reactor Netty HTTP server denial of service via pipelined requests

Source: https://junglewise.ai/threats/cve-2026-47874-reactor-netty-http-server-denial-of-service-via-pipelined  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-27. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-47874 · Severity: medium · CVSS 5.3 · Published 2026-08-27

Reactor Netty is a networking library used to build reactive HTTP servers. A vulnerability in how it handles HTTP/1.1 pipelined requests allows an attacker to send multiple requests over a single connection, causing the server to consume excessive memory and become unavailable to legitimate users, resulting in a denial of service.

## Quick answers

**Is CVE-2026-47874 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-47874 being exploited in the wild.

**How severe is CVE-2026-47874?** Medium severity, with a CVSS score of 5.3, published 27 August 2026.

**Which products and versions are affected?** Pivotal/Spring Reactor Netty 1.3.0-1.3.6, 1.1.0-1.2.18, 1.0.52 and earlier.

**Is there a fix for CVE-2026-47874?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-47874 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-47874?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in Reactor Netty's HTTP/1.1 request handling when clients send pipelined requests (multiple requests sent in quick succession on a single persistent connection without waiting for responses). The vulnerable component fails to properly manage memory buffers, leading to unbounded memory accumulation. An attacker with network access can trigger this by sending a series of pipelined HTTP/1.1 requests, causing memory exhaustion and service unavailability. No authentication is required. Patches are available in versions 1.3.7+, 1.2.19+, and 1.0.53+.

## Affected products

- Pivotal/Spring Reactor Netty 1.3.0-1.3.6, 1.1.0-1.2.18, 1.0.52 and earlier

## Timeline

- 2026-08-27: disclosed

## References

- [https://spring.io/security/cve-2026-47874](https://spring.io/security/cve-2026-47874)