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CVE-2025-55163

Netty denial of service

7.5 HIGHPublic exploitEPSS 1.10%
  1. Published13 Aug 2025

Description

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.124.Final and 4.2.4.Final, Netty is vulnerable to MadeYouReset DDoS. This is a logical vulnerability in the HTTP/2 protocol, that uses malformed HTTP/2 control frames in order to break the max concurrent streams limit - which results in resource exhaustion and distributed denial of service. This issue has been patched in versions 4.1.124.Final and 4.2.4.Final.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Netty≥ 4.2.0 < 4.2.4 · < 4.1.124

Remediation

Fixed in
Netty≥ 4.2.4

References

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Frequently asked

Is CVE-2025-55163 being actively exploited?

CVE-2025-55163 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.10%.

How severe is CVE-2025-55163?

CVE-2025-55163 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 1.10% probability of exploitation.

Which products are affected by CVE-2025-55163?

Affected products include Netty.

How do I fix CVE-2025-55163?

Upgrade affected software to a fixed version, for example Netty 4.2.4 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.