Vulnerability Description
Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.136.Final and 4.2.16.Final, Netty's STOMP encoder ( StompSubframeEncoder ) does not escape or validate header values in CONNECT and CONNECTED frames, so raw newline ( \n ) characters in a header value are written directly to the wire, allowing an attacker who controls a header value to inject additional STOMP headers. This happens because the encoder intentionally skips escaping for CONNECT/CONNECTED frames per the STOMP 1.2 specification but never rejects the raw newlines, and since a broker parses each line as a separate header, an attacker controlling a value such as a user-supplied login or passcode can overwrite connection parameters or add authentication/role headers to bypass authentication or escalate privileges (the actual impact is broker-dependent). The issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Netty | Netty | < 4.1.136 |
Related Weaknesses (CWE)
References
- https://github.com/netty/netty/security/advisories/GHSA-3g8r-4pfx-jmfhMitigationVendor Advisory
- https://github.com/netty/netty/security/advisories/GHSA-3g8r-4pfx-jmfhMitigationVendor Advisory
FAQ
What is CVE-2026-59920?
CVE-2026-59920 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.136.Final and 4.2.16.Final, Netty's STOMP encoder ( StompSubframeEncoder ) does not escape or validate he...
How severe is CVE-2026-59920?
CVE-2026-59920 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59920?
Check the references section above for vendor advisories and patch information. Affected products include: Netty Netty.