Netty XMLFrameDecoder DoS via Repeated ClosingTags Pre-4.1.136/4.2.16
CVE-2026-73507 Published on August 13, 2026
Netty: Denial of Service in XmlFrameDecoder via CPU Exhaustion
Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.xml.XmlFrameDecoder.decode() failed to preserve closing-tag parser state across invocations, so an unauthenticated remote attacker could trickle-feed repeated </ sequences that repeatedly rescanned the accumulated buffer and exhausted an EventLoop thread's CPU, causing denial of service with a maxFrameLength of 1 MB. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
Vulnerability Analysis
CVE-2026-73507 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2026-73507 has been classified to as a Resource Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-73507
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Affected Versions
netty:- Version < 4.1.136.Final is affected.
- Version >= 4.2.0.Final, < 4.2.16.Final is affected.