Vulnerability Description
Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty HTTP/2 max header size handling produces an attack similar to HTTP/2 Rapid Reset. There is a setting in the http2 specification called `SETTINGS_MAX_HEADER_LIST_SIZE`. When a client sends that setting to Netty, it appears that Netty will behave as follows: read the request; proxy the request to the origin; attempt to produce a response; and create an exception while writing the headers for the response. Functionally, this should be similar to the http2 reset attack, but with a different on-the-wire signature. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Netty | Netty | < 4.1.135 |
Related Weaknesses (CWE)
References
- https://github.com/netty/netty/releases/tag/netty-4.1.135.FinalRelease Notes
- https://github.com/netty/netty/releases/tag/netty-4.2.15.FinalRelease Notes
- https://github.com/netty/netty/security/advisories/GHSA-563q-j3cm-6jxmVendor Advisory
- https://www.rfc-editor.org/rfc/rfc9113.html#name-defined-settingsNot Applicable
FAQ
What is CVE-2026-50560?
CVE-2026-50560 is a vulnerability with a CVSS score of 5.3 (MEDIUM). Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty HTTP/2 max header size handling produces an attack sim...
How severe is CVE-2026-50560?
CVE-2026-50560 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-50560?
Check the references section above for vendor advisories and patch information. Affected products include: Netty Netty.