Allocation of Resources Without Limits or Throttling Affecting io.netty:netty-codec-http3 package, versions [4.2.0.Final,4.2.18.Final)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JAVA-IONETTY-20154839
- published27 Sept 2026
- disclosed26 Sept 2026
- credithussst
Introduced: 26 Sep 2026
NewCVE-2026-100660 (opens in a new tab)How to fix?
Upgrade io.netty:netty-codec-http3 to version 4.2.18.Final or higher.
Overview
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the streamSectionTrackers map of QpackEncoder, populated by encodeHeaders(), which keeps a queue and dynamic-table index tracker for every encoded field section that references the dynamic table and removes entries only on a Section Acknowledgment or Stream Cancellation from the peer decoder, with no bound on tracked streams, field sections, or retained bytes. An attacker can force unbounded heap retention, reaching heavy garbage-collection pressure and OutOfMemoryError, by advertising a non-zero QPACK dynamic-table capacity, sending a single valid Insert Count Increment to signal receipt, then withholding every mandatory Section Acknowledgment while opening requests sequentially, which keeps the activity under concurrent-stream limits. This requires the server to emit repeatable, non-sensitive response headers eligible for dynamic indexing, and the growth persists for the lifetime of the connection.