Service hang via repeated XmlFrameDecoder buffer rescans
Published Aug 13, 2026 · Updated Aug 13, 2026
Denial of service in Netty before 4.1.136.Final and 4.2.16.Final allows remote attackers to hang an EventLoop thread. XmlFrameDecoder.decode() discards closing-tag parser progress between calls, so each trickled </ sequence makes it rescan the entire buffered payload for a closing >. Exploitation requires an exposed Netty server using XmlFrameDecoder; a 1 MB maxFrameLength is sufficient to monopolize one EventLoop thread without reading or altering data.
Summary
What happened
Denial of service in Netty before 4.1.136.Final and 4.2.16.Final allows remote attackers to hang an EventLoop thread. XmlFrameDecoder.decode() discards closing-tag parser progress between calls, so each trickled </ sequence makes it rescan the entire buffered payload for a closing >. Exploitation requires an exposed Netty server using XmlFrameDecoder; a 1 MB maxFrameLength is sufficient to monopolize one EventLoop thread without reading or altering data.
The record
- CVE
- CVE-2026-73507
- Published
- Aug 13, 2026
- Updated
- Aug 13, 2026
- Vendor
- The Netty Project
- Product
- Netty
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 13, 2026CVE publishedPublication date reported by the CVE source.
- Aug 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 4.1.136.Final
- Affected versionversion=>= 4.2.0.Final, < 4.2.16.Final
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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