Description
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final, when decoding header blocks, the non-Huffman branch of io.netty.handler.codec.http3.QpackDecoder#decodeHuffmanEncodedLiteral may execute new byte[length] for a string literal before verifying that length bytes are actually present in the compressed field section. The wire encoding allows a very large length to be expressed in few bytes. There is no check that length <= in.readableBytes() before new byte[length]. This vulnerability is fixed in 4.2.13.Final.
Published: 2026-05-13
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-2c5c-chwr-9hqw Netty HTTP/3 QPACK literal unbounded allocation
History

Thu, 14 May 2026 15:00:00 +0000

Type Values Removed Values Added
First Time appeared Io.netty
Io.netty netty-codec-http3
Netty
Netty netty
Vendors & Products Io.netty
Io.netty netty-codec-http3
Netty
Netty netty

Wed, 13 May 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 13 May 2026 18:30:00 +0000

Type Values Removed Values Added
Description Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final, when decoding header blocks, the non-Huffman branch of io.netty.handler.codec.http3.QpackDecoder#decodeHuffmanEncodedLiteral may execute new byte[length] for a string literal before verifying that length bytes are actually present in the compressed field section. The wire encoding allows a very large length to be expressed in few bytes. There is no check that length <= in.readableBytes() before new byte[length]. This vulnerability is fixed in 4.2.13.Final.
Title Netty: HTTP/3 QPACK literal unbounded allocation
Weaknesses CWE-770
CWE-789
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Subscriptions

Io.netty Netty-codec-http3
Netty Netty
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-13T19:35:35.549Z

Reserved: 2026-04-28T17:26:12.085Z

Link: CVE-2026-42582

cve-icon Vulnrichment

Updated: 2026-05-13T19:35:31.046Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-13T19:17:23.763

Modified: 2026-05-14T16:26:50.047

Link: CVE-2026-42582

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-14T14:34:07Z

Weaknesses