Quick answers
- Is CVE-2026-93558 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-93558 being exploited in the wild.
- How severe is CVE-2026-93558?
- High severity, with a CVSS score of 7.5, published 18 September 2026.
- Which products and versions are affected?
- Netty <UNKNOWN>.
- Is there a fix for CVE-2026-93558?
- 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-2026-93558 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-93558?
- 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 WebSocketServerExtensionHandler component and involves improper handling of HTTP/1.1 pipelined requests. An attacker can exploit this by sending multiple HTTP requests in rapid succession over a single connection, causing them to queue unbounded in memory. The handler fails to properly limit queue growth, leading to heap exhaustion in the Java Virtual Machine and a denial-of-service condition. No authentication is required; the attack is triggered via network-accessible HTTP requests. A patch addressing queue management should be available from the Netty project.
Affected products
- Netty Netty <UNKNOWN>
Timeline
- 2026-09-18: disclosed