CVE-2026-42582

HIGH

Netty: HTTP/3 QPACK literal unbounded allocation

Title source: cna
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v3 7.5
EPSS 0.0044
EPSS Percentile 34.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-770 CWE-789
Status published
Products (4)
io.netty/netty-codec-http3 0 - 4.2.13.FinalMaven
io.netty/netty-codec-http3 >= 4.2.0.Alpha1, < 4.2.13.Final
netty/netty < 4.2.13
netty/netty >= 4.2.0.Alpha1, < 4.2.13.Final
Published May 13, 2026
Tracked Since May 14, 2026