vulnerability / NVI-00015143 / Revision 1
Netty epoll transport denial of service via RST on half-closed TCP connection
GitHub lists this reviewed advisory for io.netty:netty-transport-classes-epoll. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
io.netty:netty-transport-classes-epoll
source listed>= 4.2.0.Final, < 4.2.13.Final
## Summary 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. ## Affected versions All versions of 4.2.x `netty-transport-classes-epoll` up to and including 4.2.12.Final ## Fixed in 4.2.13.Final (fix merged into the `4.2` branch via #16689; release not yet cut as of 2026-04-25). ## Severity **Medium** — Denial of Service (resource exhaustion / CPU spin) **CVSS:** 3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - **7.5** **CWE:** CWE-772: Missing Release of Resource after Effective Lifetime ## Description When a TCP connection using Netty's epoll transport has `ALLOW_HALF_CLOSURE` enabled (or is in a half-closed state via the HTTP codec), and the remote peer: 1. Sends a FIN (half-close), causing the server to mark the input as shutdown, then 2. Sends a RST (e.g. by closing with `SO_LINGER=0`) the server-side channel is never closed. This happens because: - `epollOutReady()` is a no-op when there is no pending flush. - `epollInReady()` short-circuits via
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-rwm7-x88c-3g2p ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.