CVE-2026-59901

HIGH

Netty Bzip2Decoder: Infinite Loop in RLE State Machine Leads to Event-Loop Thread Hang

Title source: cna
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v4 8.7
EPSS 0.0025
EPSS Percentile 15.9%
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-835
Status published
Products (2)
netty/netty < 4.1.136.Final
netty/netty >=4.2.0.Final, < 4.2.16.Final
Published Jul 29, 2026
Tracked Since Jul 29, 2026