CVE-2025-58057: Netty's BrotliDecoder is vulnerable to DoS via zip bomb style attack

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-09-04 · updated 2026-10-19
Weakness: CWE-409

Description

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In netty-codec-compression versions 4.1.124.Final and below, and netty-codec versions 4.2.4.Final and below, when supplied with specially crafted input, BrotliDecoder and certain other decompression decoders will allocate a large number of reachable byte buffers, which can lead to denial of service. BrotliDecoder.decompress has no limit in how often it calls pull, decompressing data 64K bytes at a time. The buffers are saved in the output list, and remain reachable until OOM is hit. This is fixed in versions 4.1.125.Final of netty-codec and 4.2.5.Final of netty-codec-compression.

Affected products

netty: before 4.1.125; from 4.2.0 before 4.2.5 — fixed in 4.1.125, 4.2.5

How to fix

Upgrade to a fixed version: netty 4.1.125, 4.2.5. Check the vendor advisory for mitigations.

References

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