High severity · published May 13, 2026
CVE-2026-42577
Netty: epoll transport denial of service via RST on half-closed TCP connection
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 35% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NE
netty · netty
>= 4.2.0.Final, < 4.2.13.Final · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42577
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42577
Patch
https://github.com/netty/netty/commit/0ec3d97fab376e243d328ac95fbd288ba0f6e22d
Issue Tracking
https://github.com/netty/netty/pull/16689
Mitigation
https://github.com/netty/netty/security/advisories/GHSA-rwm7-x88c-3g2p
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