What is CVE-2026-42582?

CVE-2026-42582 is a high-severity vulnerability in Io.netty Netty-codec-http3, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-05-13.

How severe is CVE-2026-42582?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Io.netty Netty-codec-http3

CVE-2026-42582

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[…

EPSS: 0.000 (4.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Io.netty Netty-codec-http3 — versions >= 4.2.0.Alpha1, < 4.2.13.Final
Netty — versions >= 4.2.0.Alpha1, < 4.2.13.Final

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42582?: CVE-2026-42582 is a high-severity vulnerability in Io.netty Netty-codec-http3, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-05-13.
How severe is CVE-2026-42582?: High severity. CVSS v3 base score is 7.5 out of 10.