---
cve: "CVE-2026-42587"
severity: "HIGH"
cvss: 7.5
epss: "99%"
vendor: "io.netty"
kev: false
exploited: false
published: "2026-05-13 18:22:21"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T10:27:17+02:00"
---

# CVE-2026-42587

> 7.5 HIGH · 🧪 PoC

## Beschreibung

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.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)

- fb13125f135ab53203513ff603872a3abe84d38d (Commit)
- b3844c8108b42f68d56144b36d4d1ed96078a688 (Commit)

## Referenzen

- <https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-42587) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_