Quick answers
- Is CVE-2026-93566 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-93566 being exploited in the wild.
- How severe is CVE-2026-93566?
- Medium severity, with a CVSS score of 6.5, published 18 September 2026.
- Which products and versions are affected?
- Netty Netty.
- Is there a fix for CVE-2026-93566?
- 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-2026-93566 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-93566?
- Check whether you run Netty. 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 is an HTTP request smuggling flaw (CWE-444) in Netty's HTTP chunk decoding logic. The root cause is insufficient validation of control characters within the chunk-size line of chunked transfer encoding. A remote, unauthenticated attacker can send a crafted HTTP request that exploits this validation bypass to inject arbitrary HTTP requests. The attack vector is network-based and requires no authentication or special preconditions. Successful exploitation can lead to request smuggling, information disclosure, and unauthorized actions. Patches are expected from the Netty project.
Affected products
- Netty Netty
Timeline
- 2026-09-18: disclosed