netty: Improper Handling of Highly Compressed Data (Data Amplification)
CVE-2025-58057 is a high-severity improper handling of highly compressed data (data amplification) vulnerability in netty, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected netty versions: <= 4.1.124.Final, < 4.1.125.Final; <= 4.2.4.Final, < 4.2.5.Final. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of netty you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Netty | netty | <= 4.1.124.Final, < 4.1.125.Final; <= 4.2.4.Final, < 4.2.5.Final | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 6.9 | Medium | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Handling of Highly Compressed Data (Data Amplification)
The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
More Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities (CWE-409)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
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Recent Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities
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