🛡️ CVE-2026-59901 — netty

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-835 NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the Bzip2Decoder handler in Netty's compression codec pipeline is vulnerable to a denial-of-service attack through a malformed bzip2 stream that permanently captures the event-loop thread in an infinite loop. The vulnerability exists in the run-length encoding (RLE) state machine within [Bzip2BlockDecompressor.read()]. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2026-59901 is classified as CWE-835: Infinite Loop. A loop condition can never become false for some inputs, hanging the process.

Affected software

CVE-2026-59901 is recorded against 3 packages.

  • io.netty:netty-codec (fixed in 4.1.136.Final)
  • io.netty:netty-codec-compression (from 4.2.0.Final up to 4.2.16.Final)
  • netty (from 4.2.0 up to 4.2.16)

Timeline and source

Published on 22 July 2026 and last revised on 23 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
github.com (Package)
github.com (Web)
github.com (Web)

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-835
Public Exploit ✅ No
Source NVD
Published 2026-07-22
Updated 2026-08-12
Modified 2026-07-23
Fix URL N/A

Affected Packages

Software From version Fixed in
io.netty:netty-codec — 4.1.136.Final
io.netty:netty-codec-compression 4.2.0.Final 4.2.16.Final
netty 4.2.0 4.2.16

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