---
cve: "CVE-2026-56819"
severity: "HIGH"
cvss: 7.5
epss: "37%"
vendor: "netty"
kev: false
exploited: false
published: "2026-07-21 23:17:52"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-11T13:01:31+02:00"
---

# CVE-2026-56819

> 7.5 HIGH · 🧪 PoC

## Beschreibung

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct `ByteBuf` per HTTP/2 `DATA` frame in applications that enable HTTP/2 content decompression via `DelegatingDecompressorFrameListener`. When a `DATA` frame is processed for a stream whose decompressor has already been closed, `Http2Decompressor.decompress(...)` calls `decompressor.writeInbound(data.retain())` and does not release the retained buffer on the error path, eventually exhausting direct memory and crashing the JVM. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- fca0764703b3bb59c6e6dc5d29c6d9710d35c0e6 (Commit)
- 3703d79669ee024f6483c9d8697ac58ba546df33 (Commit)

## Referenzen

- <https://github.com/netty/netty/security/advisories/GHSA-93wv-jw9v-4972>
- <https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b>
- <https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6>
- <https://github.com/netty/netty/releases/tag/netty-4.1.136.Final>
- <https://github.com/netty/netty/releases/tag/netty-4.2.16.Final>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-56819) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_