---
cve: "CVE-2026-56745"
severity: "HIGH"
cvss: 8.7
epss: "61%"
vendor: "netty"
kev: false
exploited: false
published: "2026-07-21 22:17:14"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-05T22:45:36+02:00"
---

# CVE-2026-56745

> 8.7 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, the `SpdyHttpDecoder` handler in Netty's SPDY-to-HTTP codec allocates a pooled `ByteBuf` when processing a client-initiated `SYN_STREAM` frame with `FLAG_FIN=0` and stores the partially constructed `FullHttpRequest` in `messageMap`; when the remote peer sends `RST_STREAM` for that stream or the accumulated content exceeds `maxContentLength`, the decoder removes the entry but does not release the pooled `ByteBuf`, causing native memory exhaustion. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- fca0764703b3bb59c6e6dc5d29c6d9710d35c0e6 (Commit)
- 3703d79669ee024f6483c9d8697ac58ba546df33 (Commit)

## Referenzen

- <https://github.com/netty/netty/security/advisories/GHSA-jppx-w49h-x2qq>
- <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-2026-56745) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_