# CVE-2026-93492: Netty HTTP/2 HpackEncoder Denial of Service

Source: https://junglewise.ai/threats/cve-2026-93492-netty-http-2-hpackencoder-denial-of-service  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-93492 · Severity: medium · CVSS 5.3 · Published 2026-09-18

Netty is a networking framework widely used in Java applications to handle HTTP and other network protocols. A vulnerability in its HTTP/2 implementation allows a remote attacker to trigger excessive memory and CPU consumption by sending specially crafted HTTP/2 frames, causing the application to become unresponsive or crash. This can disrupt services that depend on Netty for network communication.

Technologies: [Netty](https://junglewise.ai/threats/technologies/netty). Vendors: [Netty](https://junglewise.ai/threats/vendors/netty).

## Quick answers

**Is CVE-2026-93492 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-93492 being exploited in the wild.

**How severe is CVE-2026-93492?** Medium severity, with a CVSS score of 5.3, published 18 September 2026.

**Which products and versions are affected?** Netty <UNKNOWN>.

**Is there a fix for CVE-2026-93492?** 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-2026-93492 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-93492?** Check whether you run Netty at an affected version. 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 Netty's HpackEncoder component within the HTTP/2 protocol handler. An attacker can send HTTP/2 SETTINGS frames with an extremely large MAX_HEADER_TABLE_SIZE value, which causes the encoder to allocate and store excessive memory for header tables. This triggers uncontrolled resource consumption (CPU and memory), leading to a Denial of Service condition. The attack is remotely exploitable over the network without authentication or user interaction required. No patch status is indicated in the available advisory text.

## Affected products

- Netty Netty <UNKNOWN>

## Timeline

- 2026-09-18: disclosed

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/jbossnetwork/restricted/listSoftware.html](https://access.redhat.com/jbossnetwork/restricted/listSoftware.html)

## Related threats

- [Netty HTTP/1 decoder request smuggling](https://junglewise.ai/threats/cve-2026-93562-a-flaw-was-found-in-netty-s-http-1-decoder-incomplete-validation)
- [Netty HTTP/1 to HTTP/2 conversion authority mismatch](https://junglewise.ai/threats/cve-2026-93569-netty-http-1-to-http-2-conversion-authority-mismatch)
- [Netty HTTP request smuggling via control characters in chunk size](https://junglewise.ai/threats/cve-2026-93566-netty-http-request-smuggling-via-control-characters-in-chunk-size)
- [Netty RtspDecoder method-token smuggling in RTSP parsing](https://junglewise.ai/threats/cve-2026-93565-netty-rtspdecoder-method-token-smuggling-in-rtsp-parsing)
- [Netty reference-count leak in HAProxy PROXY-v2 decoder](https://junglewise.ai/threats/cve-2026-93564-netty-reference-count-leak-in-haproxy-proxy-v2-decoder)