Vulnerability · Published Jun 12, 2026 · Assigned by GitHub_M
CVE-2026-50009Netty QUIC stateless reset token material exposed through header-visible connection IDs
Medium 4.8
In plain English
A medium-severity information exposure in netty from netty. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Netty is a network application framework for development of protocol servers and clients. Prior to version 4.2.15.Final, Netty QUIC exposes the stateless reset token on the network path when using the default HMAC-based connection-ID and stateless-reset-token generators. The reset token for the server's current source connection ID can be derived from bytes that appear as the connection ID in QUIC headers after a source-CID rotation. An on-path attacker observing the headers can use the token to perform a Denial of Service by sending a spoofed Stateless Reset packet. Version 4.2.15.Final patches the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | netty | no fix listed | DEBIAN-CVE-2026-50009 |
| Debian:13 | netty | no fix listed | DEBIAN-CVE-2026-50009 |
| Debian:14 | netty | no fix listed | DEBIAN-CVE-2026-50009 |
| Maven | io.netty:netty-codec-classes-quic | 4.2.15.Final | GHSA-cq4q-cv5g-r8q5 |
| Ubuntu:25.10 | netty | no fix listed | UBUNTU-CVE-2026-50009 |
| Ubuntu:26.10 | netty | no fix listed | UBUNTU-CVE-2026-50009 |
Affected products (as reported)
Weakness: CWE-200, CWE-330 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
References
- https://github.com/netty/netty/security/advisories/GHSA-cq4q-cv5g-r8q5 x_refsource_CONFIRM
- https://github.com/netty/netty/releases/tag/netty-4.2.15.Final x_refsource_MISC