Vulnerability in Netty
CVE-2026-42577
Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100% CPU busy-loop in the event loop thread. This vulnerability is fixed in 4.2.13.Final.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (45.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 45.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- Netty — versions >= 4.2.0.Final, < 4.2.13.Final
Weakness classification (CWE)
References
- github.com/netty/netty/security/advisories/GHSA-rwm7-x88c-3g2p (Mitigation, Vendor Advisory)
- github.com/netty/netty/pull/16689 (Patch, Issue Tracking)
- github.com/netty/netty/commit/0ec3d97fab376e243d328ac95fbd288ba0f6e22d (Patch)
Frequently asked questions
- What is CVE-2026-42577?
- CVE-2026-42577 is a high-severity vulnerability in Netty, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 7.5/10. Published 2026-05-13.
- How severe is CVE-2026-42577?
- High severity. CVSS v3 base score is 7.5 out of 10.